bugreport.texi, [...]: Avoid some first-person references and patronizing comments.

bugreport.texi, [...]: Avoid some first-person references and patronizing comments.

	* doc/bugreport.texi, doc/configterms.texi, doc/contrib.texi,
	doc/contribute.texi, doc/cpp.texi, doc/cppinternals.texi,
	doc/extend.texi, doc/install.texi, doc/invoke.texi, doc/md.texi,
	doc/portability.texi, doc/tree-ssa.texi, doc/trouble.texi: Avoid
	some first-person references and patronizing comments.  Based on
	printed manual.
	* doc/invoke.texi: Don't reference fortran@gnu.org.
	* doc/trouble.texi (Warning when a non-void function value is
	ignored): Rewrite.  From Russ Allbery and Chris Devers.

From-SVN: r84034