Make search on by default

Author: pmarsceill

_includes/head.html

@@ -26,7 +26,7 @@
 
   {% endif %}
 
-  {% if site.search_enabled != nil %}
+  {% if site.search_enabled != false %}
     <script type="text/javascript" src="{{ '/assets/js/vendor/lunr.min.js' | absolute_url }}"></script>
   {% endif %}
   <script type="text/javascript" src="{{ '/assets/js/just-the-docs.js' | absolute_url }}"></script>

_layouts/default.html

@@ -25,7 +25,7 @@
     <div class="main-content-wrap js-main-content" tabindex="0">
       <div class="main-content">
         <div class="page-header js-page-header">
-          {% if site.search_enabled != nil %}
+          {% if site.search_enabled != false %}
           <div class="search">
             <div class="search-input-wrap">
               <input type="text" class="js-search-input search-input" tabindex="0" placeholder="Search {{ site.title }}" aria-label="Search {{ site.title }}" autocomplete="off">