Add missing options to option summary [PR122243]

Add missing options to option summary [PR122243]

I noticed that several options (mostly C++ options, including those
for contracts) were documented in the manual but were not listed in
the corresponding option summary table.  Besides adding the entries, I
also corrected the alphabetization in the C++ option table and some
formatting issues for option arguments.

gcc/ChangeLog
	PR other/122243
	* doc/invoke.texi (Option Summary): Add missing entries,
	also correct alphabetization and formatting of the C++ options.
	(C++ Language Options): Fix some formatting issues.