[theme] /preferences: rename "Method" to "HTTP Method"

Closes: https://github.com/searxng/searxng/issues/751
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/templates/oscar/preferences.html

@@ -259,7 +259,7 @@
                 <fieldset>
                     <div class="container-fluid">
                         {% if 'method' not in locked_preferences %}
-                        {% set method_label = _('Method') %}
+                        {% set method_label = _('HTTP Method') %}
                         {% set method_info = _('Change how forms are submited, <a href="http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Request_methods" rel="external">learn more about request methods</a>') %}
                         {{ preferences_item_header(method_info, method_label, rtl, 'method') }}
                             <select class="form-control {{ custom_select_class(rtl) }}" name="method" id="method">

searx/templates/simple/preferences.html

@@ -234,7 +234,7 @@
   {{ tab_header('maintab', 'privacy', _('Privacy')) }}
     {% if 'method' not in locked_preferences %}
     <fieldset>
-      <legend>{{ _('Method') }}</legend>
+      <legend>{{ _('HTTP Method') }}</legend>
       <p class="value">
         <select name='method'>
           <option value="POST" {% if method == 'POST' %}selected="selected"{% endif %}>POST</option>