commit: typofix for xxFFF[EF] check

We wanted to catch all codepoints that ends with FFFE and FFFF,
not with 0FFFE and 0FFFF.

Noticed and corrected by Peter Krefting.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/commit.c b/commit.c
index 7dcfeea..38d8979 100644
--- a/commit.c
+++ b/commit.c
@@ -1306,7 +1306,7 @@
 		if ((codepoint & 0x1ff800) == 0xd800)
 			return bad_offset;
 		/* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
-		if ((codepoint & 0xffffe) == 0xfffe)
+		if ((codepoint & 0xfffe) == 0xfffe)
 			return bad_offset;
 		/* So are anything in the range U+FDD0..U+FDEF. */
 		if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)