diff-highlight: ignore test cruft

These are the same as in the normal t/.gitignore, with the
exception of ".prove", as our Makefile does not support it.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

contrib/diff-highlight/t/.gitignore

@@ -0,0 +1,2 @@
+/trash directory*
+/test-results