[fix] oscar theme - preferences: rename col-checkbox/col-stat

[1] https://github.com/searxng/searxng/pull/295#discussion_r703318053
[2] https://github.com/searxng/searxng/pull/295#discussion_r703337237

Suggested-by: @dalf [1] [2]
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/static/themes/oscar/src/less/preferences.less

@@ -1,3 +1,3 @@
-.col-checkbox {
+.col-stat {
     width: 10rem;
 }

searx/templates/oscar/preferences.html

@@ -318,15 +318,15 @@
                                     <th scope="col">{{ _("Allow") }}</th>
                                     <th scope="col">{{ _("Engine name") }}</th>
                                     <th scope="col">{{ _("Shortcut") }}</th>
-                                    <th scope="col" class="col-checkbox">{{ _("Selected language") }}</th>
-                                    <th scope="col" class="col-checkbox">{{ _("SafeSearch") }}</th>
-                                    <th scope="col" class="col-checkbox">{{ _("Time range") }}</th>
+                                    <th scope="col" class="col-stat">{{ _("Selected language") }}</th>
+                                    <th scope="col" class="col-stat">{{ _("SafeSearch") }}</th>
+                                    <th scope="col" class="col-stat">{{ _("Time range") }}</th>
                                     <th scope="col">{{ _("Response time") }}</th>
-                                    <th scope="col" class="col-checkbox text-right">{{ _("Max time") }}</th>
-                                    <th scope="col" class="col-checkbox text-right">{{ _("Reliablity") }}</th>
+                                    <th scope="col" class="col-stat text-right">{{ _("Max time") }}</th>
+                                    <th scope="col" class="col-stat text-right">{{ _("Reliablity") }}</th>
                                     {% else %}
-                                    <th scope="col">{{ _("Reliablity") }}</th>
-                                    <th scope="col">{{ _("Max time") }}</th>
+                                    <th scope="col" class="col-stat">{{ _("Reliablity") }}</th>
+                                    <th scope="col" class="col-stat">{{ _("Max time") }}</th>
                                     <th scope="col" class="text-right">{{ _("Response time") }}</th>
                                     <th scope="col" class="text-right">{{ _("Time range") }}</th>
                                     <th scope="col" class="text-right">{{ _("SafeSearch") }}</th>