Editor, link checker:

- Add white outline for contrast on darker backgrounds.
- Change red colour in toolbar.

Props iseulde. Props rockwell15 for the initial patch.
See #36638.
Built from https://develop.svn.wordpress.org/trunk@37751


git-svn-id: http://core.svn.wordpress.org/trunk@37716 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/css/editor.css

@@ -1758,11 +1758,7 @@ div.wp-link-preview a {
 }
 
 div.wp-link-preview a.wplink-url-error {
-	color: #a00;
-}
-
-div.wp-link-preview a.wplink-url-error:hover {
-	color: #f00;
+	color: #dc3232;
 }
 
 div.wp-link-input {