fix(index): label class in search form

Author: line-o

src/main/xar-resources/index.html

@@ -3,7 +3,7 @@
     <h1>XQuery Function Documentation</h1>
     <form id="fun-query-form" name="f-query" class="form-horizontal" action="?" method="POST">
         <div class="row mb-3">
-            <label class="col-from-label col-md-2 hidden-xs">Search</label>
+            <label class="col-form-label col-md-2 hidden-xs">Search</label>
             <div class="col-md-4 col-xs-12">
                 <span class="input-group">
                     <input id="query-field" name="q" type="text" data-template="templates:form-control" class="form-control"/>