* doc/c-tree.texi, doc/contrib.texi, doc/cpp.texi,
	doc/cppinternals.texi, doc/extend.texi, doc/gcc.texi,
	doc/gcov.texi, doc/install-old.texi, doc/install.texi,
	doc/invoke.texi, doc/md.texi, doc/rtl.texi, doc/tm.texi: Replace
	. at end of sentences preceded by a capital letter with @..

From-SVN: r43611