emacs: Improve doc-strings

- The first sentence should fit on the first line in full.  This is
  even the case when that causes the line to get a bit long.  If it
  gets very long, then it should be made shorter.

- Even even the second sentence would fit on the first line, if it
  just provides some details, then it shouldn't be done.

- Symbols are quoted like `so'.

- There is no clear rule on how to (not) quote non-atomic
  s-expressions, but quoting like '(this) is definitely weird.

- It is a good idea to remember that \" becomes " and to take
  that in mind when adjusting the automatic filling by hand.

- Use the imperative form.

- Arguments are written in all uppercase.

emacs/notmuch-address.el

@@ -36,9 +36,9 @@
 This variable is set by calling `notmuch-address-harvest'.")
 
 (defvar notmuch-address-full-harvest-finished nil
-  "t indicates that full completion address harvesting has been
-finished. Use notmuch-address--harvest-ready to access as that
-will load a saved hash if necessary (and available).")
+  "t indicates that full completion address harvesting has been finished.
+Use notmuch-address--harvest-ready to access as that will load a
+saved hash if necessary (and available).")
 
 (defun notmuch-address--harvest-ready ()
   "Return t if there is a full address hash available.
@@ -54,9 +54,9 @@ If it is a string then that string should be an external program
 which must take a single argument (searched string) and output a
 list of completion candidates, one per line.
 
-Alternatively, it can be the symbol 'internal, in which case
+Alternatively, it can be the symbol `internal', in which case
 internal completion is used; the variable
-`notmuch-address-internal-completion` can be used to customize
+`notmuch-address-internal-completion' can be used to customize
 this case.
 
 Finally, if this variable is nil then address completion is
@@ -72,12 +72,12 @@ disabled."
 (defcustom notmuch-address-internal-completion '(sent nil)
   "Determines how internal address completion generates candidates.
 
-This should be a list of the form '(DIRECTION FILTER), where
+This should be a list of the form (DIRECTION FILTER), where
 DIRECTION is either sent or received and specifies whether the
 candidates are searched in messages sent by the user or received
 by the user (note received by is much faster), and FILTER is
-either nil or a filter-string, such as \"date:1y..\" to append
-to the query."
+either nil or a filter-string, such as \"date:1y..\" to append to
+the query."
   :type '(list :tag "Use internal address completion"
 	       (radio
 		:tag "Base completion on messages you have"
@@ -101,8 +101,8 @@ to the query."
   "Filename to save the cached completion addresses.
 
 All the addresses notmuch uses for address completion will be
-cached in this file. This has obvious privacy implications so you
-should make sure it is not somewhere publicly readable."
+cached in this file.  This has obvious privacy implications so
+you should make sure it is not somewhere publicly readable."
   :type '(choice (const :tag "Off" nil)
 		 (file :tag "Filename"))
   :group 'notmuch-send
@@ -110,12 +110,14 @@ should make sure it is not somewhere publicly readable."
   :group 'notmuch-external)
 
 (defcustom notmuch-address-selection-function 'notmuch-address-selection-function
-  "The function to select address from given list. The function is
-called with PROMPT, COLLECTION, and INITIAL-INPUT as arguments
-(subset of what `completing-read' can be called with).
-While executed the value of `completion-ignore-case' is t.
-See documentation of function `notmuch-address-selection-function'
-to know how address selection is made by default."
+  "The function to select address from given list.
+
+The function is called with PROMPT, COLLECTION, and INITIAL-INPUT
+as arguments (subset of what `completing-read' can be called
+with).  While executed the value of `completion-ignore-case'
+is t.  See documentation of function
+`notmuch-address-selection-function' to know how address
+selection is made by default."
   :type 'function
   :group 'notmuch-send
   :group 'notmuch-address
@@ -188,9 +190,9 @@ The candidates are taken from `notmuch-address-completions'."
     candidates))
 
 (defun notmuch-address-options (original)
-  "Returns a list of completion candidates. Uses either
-elisp-based implementation or older implementation requiring
-external commands."
+  "Return a list of completion candidates.
+Use either elisp-based implementation or older implementation
+requiring external commands."
   (cond
    ((eq notmuch-address-command 'internal)
     (unless (notmuch-address--harvest-ready)
@@ -352,7 +354,7 @@ execution, CALLBACK is called when harvesting finishes."
   "Version format of the save hash.")
 
 (defun notmuch-address--get-address-hash ()
-  "Returns the saved address hash as a plist.
+  "Return the saved address hash as a plist.
 
 Returns nil if the save file does not exist, or it does not seem
 to be a saved address hash."

emacs/notmuch-query.el

@@ -47,22 +47,21 @@ is a possibly empty forest of replies."
 	  seq)))
 
 (defun notmuch-query-map-threads (fn threads)
-  "Apply FN to every thread in THREADS. Flatten results to a list.
-
-See the function notmuch-query-get-threads for more information."
+  "Apply function FN to every thread in THREADS.
+Flatten results to a list.  See the function
+`notmuch-query-get-threads' for more information."
   (notmuch-query-map-aux 'notmuch-query-map-forest fn threads))
 
 (defun notmuch-query-map-forest (fn forest)
-  "Apply function to every message in a forest. Flatten results to a list.
-
-See the function notmuch-query-get-threads for more information.
-"
+  "Apply function FN to every message in FOREST.
+Flatten results to a list.  See the function
+`notmuch-query-get-threads' for more information."
   (notmuch-query-map-aux 'notmuch-query-map-tree fn forest))
 
 (defun notmuch-query-map-tree (fn tree)
-  "Apply function FN to every message in TREE. Flatten results to a list.
-
-See the function notmuch-query-get-threads for more information."
+  "Apply function FN to every message in TREE.
+Flatten results to a list.  See the function
+`notmuch-query-get-threads' for more information."
   (cons (funcall fn (car tree)) (notmuch-query-map-forest fn (cadr tree))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

emacs/notmuch-show.el

@@ -446,8 +446,8 @@ parsing fails."
     (error (cons address nil))))
 
 (defun notmuch-show-clean-address (address)
-  "Try to clean a single email ADDRESS for display.  Return
-unchanged ADDRESS if parsing fails."
+  "Try to clean a single email ADDRESS for display.
+Return unchanged ADDRESS if parsing fails."
   (let* ((clean-address (notmuch-clean-address address))
 	 (p-address (car clean-address))
 	 (p-name (cdr clean-address)))

emacs/notmuch-tree.el

@@ -587,7 +587,7 @@ Shows in split pane or whole window according to value of
 	(scroll-up)))))
 
 (defun notmuch-tree-scroll-message-window-back ()
-  "Scroll the message window back(if it exists)."
+  "Scroll the message window back (if it exists)."
   (interactive)
   (when (window-live-p notmuch-tree-message-window)
     (with-selected-window notmuch-tree-message-window
@@ -596,7 +596,8 @@ Shows in split pane or whole window according to value of
 	(scroll-down)))))
 
 (defun notmuch-tree-scroll-or-next ()
-  "Scroll the message window. If it at end go to next message."
+  "Scroll the message window.
+If it at end go to next message."
   (interactive)
   (when (notmuch-tree-scroll-message-window)
     (notmuch-tree-next-matching-message)))

emacs/notmuch.el

@@ -432,11 +432,10 @@ returns nil."
 (defun notmuch-search-foreach-result (beg end fn)
   "Invoke FN for each result between BEG and END.
 
-FN should take one argument.  It will be applied to the
-character position of the beginning of each result that overlaps
-the region between points BEG and END.  As a special case, if (=
-BEG END), FN will be applied to the result containing point
-BEG."
+FN should take one argument.  It will be applied to the character
+position of the beginning of each result that overlaps the region
+between points BEG and END.  As a special case, if (= BEG END),
+FN will be applied to the result containing point BEG."
   (let ((pos (notmuch-search-result-beginning beg))
 	;; End must be a marker in case fn changes the
 	;; text.

emacs/rstdoc.el

@@ -36,11 +36,11 @@
 (provide 'rstdoc)
 
 (defun rstdoc-batch-extract ()
-  "Extract docstrings to and from the files on the command line"
+  "Extract docstrings to and from the files on the command line."
   (apply #'rstdoc-extract command-line-args-left))
 
 (defun rstdoc-extract (in-file out-file)
-  "Write docstrings from IN-FILE to OUT-FILE"
+  "Write docstrings from IN-FILE to OUT-FILE."
   (load-file in-file)
   (let* ((definitions (cdr (assoc (expand-file-name in-file) load-history)))
 	 (doc-hash (make-hash-table :test 'eq)))
@@ -72,7 +72,7 @@
      ("\\([^\\]\\)'" . "\\1`")
      ("^[[:space:]\t]*$" . "|br|")
      ("^[[:space:]\t]" . "|indent| "))
-    "list of (regex . replacement) pairs")
+  "List of (regex . replacement) pairs.")
 
 (defun rstdoc--rst-quote-string (str)
   (with-temp-buffer