Full headline matching cleanup

Write \n instead of \xa in the regexp, this is clearer.
And make the \n optional so that also lines at the end of
the buffers will still be matched as headlines.

lisp/ChangeLog

@@ -5,6 +5,9 @@
 	(org-set-emph-re): Remove the ? from the post-match.
 	(org-emphasis-regexp-components): Add backslash to the
 	postmatch class.
+	(org-set-font-lock-defaults): Write \n instead of \xa, and make it
+	optional so that also lines at the end of the buffers will still
+	be matched as headlines.
 
 	* org-table.el (org-table-error-on-row-ref-crossing-hline):
 	Variable made obsolete.

lisp/org.el

@@ -4559,7 +4559,7 @@ between words."
 	   '(org-font-lock-hook)
 	   ;; Headlines
 	   `(,(if org-fontify-whole-heading-line
-		  "^\\(\\**\\)\\(\\* \\)\\(.*\xa\\)"
+		  "^\\(\\**\\)\\(\\* \\)\\(.*\n?\\)"
 		"^\\(\\**\\)\\(\\* \\)\\(.*\\)")
 	     (1 (org-get-level-face 1))
 	     (2 (org-get-level-face 2))