doc: style changes.

* doc/bison.texinfo: Avoid line width issues with TeX.
Upgrade ancient messages.
Move some comments to better looking places.
Add more @group.
(Mfcalc Symbol Table): Reduce variable scopes.
Prefer size_t for sizes.
Prefer declarations with an initial value.
Fix a @group environment.
(cherry picked from commit aaaa2aaef40eed197ebbd0bd45d8a66606cdb19c)

Conflicts:

	doc/bison.texinfo