Changed one tab in doc/man1/notmuch-show.rst to 8 spaces.
Removed one leading tab in doc/man5/notmuch-hooks.rst to make
the SYNOPSIS style consistent with other pages.
Previously, this was a verbatim copy of the --format=json text.
Change it to instead reference the JSON text and actually describe how
the S-expression format works.
This is the output from sphinx-quickstart, massaged a bit, along with
our existing man pages converted to rst.
A skeleton notmuch-emacs manual is also included. It is not suitable
for end user use yet.
