MDL-71965 theme: Address behat failures

* The helplink has changed so the language customisation check had to be
  updated to use a different selector.
* The totop string has been moved from boost to classic only and the
  string must be moved too.
* The new footer toggle may sit over the [next page] button for the
  timeline block for some browsers (Linux only). Changing the browser
  size to large resolves this.

AMOS BEGIN
 CPY [totop,boost],[totop,classic]
AMOS END

admin/tool/customlang/tests/behat/customisation_create.feature

@@ -21,13 +21,15 @@ Feature: Within a moodle instance, an administrator should be able to modify lan
   @javascript
   Scenario: Edit an string but don't save it to lang pack.
     When I press "Apply changes and continue editing"
-    Then I should see "Help and documentation" in the ".helplink" "css_element"
-    And I should not see "moodle documents" in the ".helplink" "css_element"
+    And I click on "Show footer" "button"
+    Then I should not see "moodle documents" in the "page-footer" "region"
+    And I should see "Help and documentation" in the "page-footer" "region"
 
   @javascript
   Scenario: Customize an string as admin and save it to lang pack.
     Given I press "Save changes to the language pack"
     And I should see "There are 1 modified strings."
     When I click on "Continue" "button"
-    Then I should see "moodle documents" in the ".helplink" "css_element"
-    And I should not see "Help and documentation" in the ".helplink" "css_element"
+    And I click on "Show footer" "button"
+    Then I should not see "Help and documentation" in the "page-footer" "region"
+    And I should see "moodle documents" in the "page-footer" "region"

blocks/timeline/tests/behat/block_timeline_dates.feature

@@ -30,6 +30,7 @@ Feature: The timeline block allows users to see upcoming activities
       | student1 | C1 | student |
       | student1 | C2 | student |
       | student1 | C3 | student |
+    And I change window size to "large"
 
   Scenario: Next 7 days in date view
     Given I log in as "student1"

theme/classic/lang/en/theme_classic.php

@@ -35,7 +35,8 @@ $string['presetfiles'] = 'Additional theme preset files';
 $string['presetfiles_desc'] = 'Preset files can be used to dramatically alter the appearance of the theme. See <a href="https://docs.moodle.org/dev/Boost_Presets">Boost presets</a> for information on creating and sharing your own preset files, and see the <a href="https://archive.moodle.net/boost">Presets repository</a> for presets that others have shared.';
 $string['preset'] = 'Theme preset';
 $string['preset_desc'] = 'Pick a preset to broadly change the look of the theme.';
+$string['privacy:metadata'] = 'The Classic theme does not store any personal data.';
 $string['region-side-post'] = 'Right';
 $string['region-side-pre'] = 'Left';
 $string['sitetitle'] = 'Site title';
-$string['privacy:metadata'] = 'The Classic theme does not store any personal data.';
+$string['totop'] = 'Go to top';

theme/classic/templates/footer.mustache

@@ -29,7 +29,7 @@
 }}
 <div id="goto-top-link">
     {{! go to top is sticky to footer so needs to be sibling }}
-    <a class="btn btn-light" role="button" href="#" aria-label="{{#str}} totop, theme_boost {{/str}}">
+    <a class="btn btn-light" role="button" href="#" aria-label="{{#str}} totop, theme_classic {{/str}}">
         {{#pix}} i/up, core{{/pix}}
     </a>
 </div>