xdiff: *.txt -> *.adoc fixes

Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

xdiff/xdiff.h

@@ -85,7 +85,7 @@ typedef struct s_xpparam {
 	regex_t **ignore_regex;
 	size_t ignore_regex_nr;
 
-	/* See Documentation/diff-options.txt. */
+	/* See Documentation/diff-options.adoc. */
 	char **anchors;
 	size_t anchors_nr;
 } xpparam_t;

xdiff/xpatience.c

@@ -64,7 +64,7 @@ struct hashmap {
 
 		/*
 		 * If 1, this entry can serve as an anchor. See
-		 * Documentation/diff-options.txt for more information.
+		 * Documentation/diff-options.adoc for more information.
 		 */
 		unsigned anchor : 1;
 	} *entries, *first, *last;