Use shorter error messages for whitespace problems

The initial version of the whitespace_error_string() function took the
messages from builtin-apply.c rather than the shorter messages from
diff.c.

This commit addresses Junio's concern that these messages might be too
long (now that we can emit multiple warnings per line).

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4015-diff-whitespace.sh

@@ -121,7 +121,7 @@ test_expect_success 'check mixed spaces and tabs in indent' '
 
 	# This is indented with SP HT SP.
 	echo " 	 foo();" > x &&
-	git diff --check | grep "Space in indent is followed by a tab"
+	git diff --check | grep "space before tab in indent"
 
 '
 

ws.c

@@ -101,16 +101,16 @@ char *whitespace_error_string(unsigned ws)
 	struct strbuf err;
 	strbuf_init(&err, 0);
 	if (ws & WS_TRAILING_SPACE)
-		strbuf_addstr(&err, "Adds trailing whitespace");
+		strbuf_addstr(&err, "trailing whitespace");
 	if (ws & WS_SPACE_BEFORE_TAB) {
 		if (err.len)
 			strbuf_addstr(&err, ", ");
-		strbuf_addstr(&err, "Space in indent is followed by a tab");
+		strbuf_addstr(&err, "space before tab in indent");
 	}
 	if (ws & WS_INDENT_WITH_NON_TAB) {
 		if (err.len)
 			strbuf_addstr(&err, ", ");
-		strbuf_addstr(&err, "Indent more than 8 places with spaces");
+		strbuf_addstr(&err, "indent with spaces");
 	}
 	return strbuf_detach(&err, NULL);
 }