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: NJunio C Hamano <gitster@pobox.com>

commit.c

@@ -1306,7 +1306,7 @@ static int find_invalid_utf8(const char *buf, int len)
 		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)