More improvements of the Emacs manual

More improvements of the Emacs manual

* doc/emacs/rmail.texi (Rmail Reply, Rmail Sorting): Improve
wording.  Suggested by Daniel Chakraborty
<danielmchakraborty@gmail.com>.

* doc/emacs/glossary.texi (Glossary): Add cross-references.
Improve and clarify wording.  Suggested by Gijs Hillenius
<gijs@hillenius.net> in emacs-manual-bugs@gnu.org.

* doc/emacs/text.texi (Org Authoring): Add more supported formats
to the list.
(TeX Print): Improve wording.  Slightly rearrange stuff.
(TeX Misc): Mention doctex-mode-hook.
(Two-Column): Minor rearrangement of text.  Suggested by Michael
Albinus <michael.albinus@gmx.de> in emacs-manual-bugs@gnu.org.

* doc/emacs/misc.texi (Saving Emacs Sessions):
* doc/emacs/programs.texi (Program Modes): Remove redundant text
and index entries.