re PR web/7596 (Broken links on g77 web page)

	Fix PR web/7596:
	* ffe.texi (Front End): Fix broken links.
	* bugs.texi (Known Bugs): Refer to gcc.gnu.org instead of
	www.gnu.org for onlinedocs.
	* news.texi (News): Ditto.

From-SVN: r56980