Fixes missing variable in input

src/definitions/elements/input.less

@@ -179,9 +179,6 @@
   box-sizing: border-box;
   transition: @iconTransition;
 }
-.ui.icon.input > .icon {
-  top: @iconOffset;
-}
 .ui.icon.input > .icon:before,
 .ui.icon.input > .icon:after {
   left: 0;
@@ -189,7 +186,7 @@
   text-align: center;
   top: 50%;
   width: 100%;
-  margin-top: -0.5em;
+  margin-top: @iconOffset;
 }
 .ui.icon.input > .link.icon {
   cursor: pointer;

src/themes/packages/default/elements/input.variables

@@ -41,7 +41,7 @@
 @iconWidth: (@verticalPadding * 2) + @glyphWidth;
 @iconOpacity: 0.5;
 @iconFocusOpacity: 1;
-/*@iconOffset: @lineHeightOffset;*/
+@iconOffset: -0.5em;
 
 @iconDistance: 0em;
 @iconMargin: @iconWidth + @iconDistance;