doc, rs6000: Clean up RS/6000 options documentation [PR122243]

doc, rs6000: Clean up RS/6000 options documentation [PR122243]

Similar to other patches in this series, the focus is on ensuring all
options are either documented or marked "Undocumented", listed in both
the options summary and detailed documentation, and both positive and
negative forms have entries in the table of contents.

gcc/ChangeLog
	PR other/122243
	* config/rs6000/darwin.opt (Waltivec-long-deprecated): Mark as
	Undocumented.
	(faltivec, ffix-and-continue, findirect-data): Likewise.
	* config/rs6000/rs6000.opt (mvrsave): Likewise.
	* config/rs6000/sysv4.opt (mno-toc, mtoc, mno-traceback): Likewise.
	(mshlib, mnewlib): Likewise.
	* doc/invoke.texi (Option Summary) <RS/6000 and PowerPC Options>:
	Document only one form of each option.  Add missing options.
	Correct whitespace.
	(RS/6000 and PowerPC Options): Separately document -mpowerpc-gpopt,
	-mpowerpc-gfxopt, -mpowerpc64, -mmfcrf, -mpopcntb, -mpopcntd,
	-mfprnd, -mcmpb, and -mhard-dfp and move their documentation after
	-mcpu=.  Remove documentation for -mtoc which is unimplemented.
	Add missing @opindex entries.  Minor copy-editing and whitespace
	fixes.