docs(icons): fix vue demo for IE

Author: Ryan A. Johnson

docs/components/icons/icon-demo.js

@@ -46,6 +46,9 @@ if (document.getElementById('vue-iconDemo')) {
             },
         },
         computed: {
+            searchPlaceholder: function () {
+                return `Search ${this.icons.length} icons for...`;
+            },
             downcaseFilter: function () {
                 return this.filter.toLowerCase();
             },

docs/components/icons/index.html

@@ -86,7 +86,7 @@ <h2 id="available-icons">Icons</h2>
         <div class="hxCol hxSpan-12-xs hxSpan-6-md hxSpan-4-xl">
           <p>
             <hx-search
-              :placeholder="`Search ${icons.length} icons for...`"
+              :placeholder="searchPlaceholder"
               :value="filter"
               @input="onFilterUpdate"
               @clear="onFilterUpdate"