remove lib-url-check() function from lib docs LESS

lib/web/css/docs/source/_utilities.less

@@ -367,66 +367,3 @@
 //        </tr>
 //    </table>
 //  </pre>
-
-// # .lib-url-check()
-//
-//  The <code>.lib-url-check()</code> mixin wraps passed value with 'url( ... )' and returns <code>@lib-url-check-output</code> variable. Can be used with <code>.lib-css()</code> mixin.
-//
-
-.example-url-check {
-    //  Set image path variable
-    @_icon-image: '/images/test.png';
-
-    //  "Call" the mixin
-    .lib-url-check(@_icon-image);
-
-    //  Will return url('/images/test.png')
-    .lib-css(background, #eee @lib-url-check-output no-repeat 0 0);
-}
-
-//
-//  If the variable is set to <code>false</code>, the <code>.lib-url-check()</code> will return false.
-//
-//  ```
-//  <div class="example-url-check">
-//      Block with background.
-//  </div>
-//  ```
-//
-
-.example-url-check-false {
-    //  Set usage image path to false
-    @_icon-image: false;
-
-    //  "Call" the mixin
-    .lib-url-check(@_icon-image);
-
-    //  Will return 'false' and outputs nothing
-    .lib-css(background, #eee @lib-url-check-output no-repeat 0 0);
-}
-
-//  ```
-//  <div class="example-url-check-false">
-//      Block with no background.
-//  </div>
-//  ```
-//
-
-//  # .lib-url-check() variables
-//
-//  <pre>
-//    <table>
-//        <tr>
-//            <th class="vars_head">Mixin variable</th>
-//            <th class="vars_head">Allowed values</th>
-//            <th class="vars_head">Output variable</th>
-//            <th class="vars_head">Comment</th>
-//        </tr>
-//        <tr>
-//            <th>@_path</th>
-//            <td class="vars_value">'' | false | value</td>
-//            <td class="vars_value">@lib-url-check-output</td>
-//            <td>Passed url to wrap in 'url( ... )'. If the 'false' value passed mixin will return 'false'</td>
-//        </tr>
-//    </table>
-//  </pre>