Fix more typos, primarily in the code

The only visible change is that git-blame doesn't understand
"--compability" anymore, but it does accept "--compatibility" instead,
which is already documented.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-diff.c

@@ -176,7 +176,7 @@ static int builtin_diff_tree(struct rev_info *revs,
 		usage(builtin_diff_usage);
 
 	/* We saw two trees, ent[0] and ent[1].
-	 * if ent[1] is unintesting, they are swapped
+	 * if ent[1] is uninteresting, they are swapped
 	 */
 	if (ent[1].item->flags & UNINTERESTING)
 		swap = 1;