cli/help,completion: added pointers to notmuch-properties(7)

completion/notmuch-completion.bash

@@ -607,7 +607,7 @@ _notmuch()
 	esac
     elif [ "${arg}" = "help" ]; then
 	# handle help command specially due to _notmuch_commands usage
-	local help_topics="$_notmuch_commands hooks search-terms"
+	local help_topics="$_notmuch_commands hooks search-terms properties"
 	COMPREPLY=( $(compgen -W "${help_topics}" -- ${cur}) )
     else
 	# complete using _notmuch_subcommand if one exist

notmuch.c

@@ -190,6 +190,8 @@ static help_topic_t help_topics[] = {
       "Common search term syntax." },
     { "hooks",
       "Hooks that will be run before or after certain commands." },
+    { "properties",
+      "Message property conventions and documentation." },
 };
 
 static command_t *