Fix for placeholder text not being grayed out in IE10

looks like a similar issue to #5166

Author: eug48

css/structure/jquery.mobile.forms.textinput.css

@@ -23,6 +23,9 @@ textarea.ui-mini { height: 45px; }
 /* Resolves issue #5166: Added to support issue introduced in Firefox 15. We can likely remove this in the future. */
 input::-moz-placeholder, textarea::-moz-placeholder { color: #aaa; }
 
+/* For IE10 */
+:-ms-input-placeholder { color: #aaa; }
+
 /* Resolves issue #5131: Width of textinput depends on its type, for Android 4.1 */
 input[type=number]::-webkit-outer-spin-button { margin: 0; }
 
@@ -40,4 +43,4 @@ input[type=number]::-webkit-outer-spin-button { margin: 0; }
 	.ui-hide-label div.ui-input-text,
 	.ui-input-search input.ui-input-text,
 	div.ui-input-text input.ui-input-text { width: 100%; }
-}
+}