Minor cleanups.

Minor cleanups.
(Comment Commands): Mention momentary Transient Mark mode.
(Matching): Be more specific about customizing show-paren-mode.
(Info Lookup): Don't list the modes that support C-h S.
Just say what it does in an unsupported mode.
(Man Page): Delete excessive info on customizing woman.
(Motion in C): Don't mention c-for/backward-into-nomenclature.