Integrate Less helper `.mixin-screen-reader-text()`

Adding Less parametric helper mixin for screen reader users.
This will help with changes such as
I7db2d7e5387f1a4392d587764598dbd82dd0a5cd

Bug: T119444
Change-Id: Ie9bce512804385578361eb77579106c799d5ff57

diff --git a/resources/src/mediawiki.less/mediawiki.mixins.less b/resources/src/mediawiki.less/mediawiki.mixins.less
index a4dca02..3535be8 100644 (file)
--- a/resources/src/mediawiki.less/mediawiki.mixins.less
+++ b/resources/src/mediawiki.less/mediawiki.mixins.less
@@ -115,3 +115,17 @@
        -ms-flex-order: @order; // IE 10
        order: @order;
 }
+
+
+// Screen Reader Helper Mixin
+.mixin-screen-reader-text() {
+       display: block;
+       position: absolute !important;
+       clip: rect( 1px, 1px, 1px, 1px );
+       width: 1px;
+       height: 1px;
+       margin: -1px;
+       border: 0;
+       padding: 0;
+       overflow: hidden;
+}