* decl.c, env.c, gigi.h, init.c, initialize.c, raise-gcc.c,
	sem_ch13.adb, sysdep.c, targtyps.c, tb-alvxw.c, tracebak.c,
	trans.c, utils.c: Fix comment typos.  Follow spelling
	conventions.
	* gnat_rm.texi, gnat_ugn.texi, : Fix typos.  Follow spelling
	conventions.

From-SVN: r114171