MDL-71373 tool_usertours: localize "previous"/"next" in user tours.

AMOS BEGIN
        CPY [previous,core],[previousstep,tool_usertours]
        CPY [next,core],[nextstep,tool_usertours]
       AMOS END

admin/tool/usertours/lang/en/tool_usertours.php

@@ -86,6 +86,7 @@ $string['newstep'] = 'Create step';
 $string['newstep'] = 'New step';
 $string['newtour'] = 'Create a new tour';
 $string['next'] = 'Next';
+$string['nextstep'] = 'Next';
 $string['options_heading'] = 'Options';
 $string['pathmatch'] = 'Apply to URL match';
 $string['pathmatch_help'] = 'Tours will be displayed on any page whose URL matches this value.
@@ -102,6 +103,7 @@ If you wish to display a tour on the Site Home page, you can use the value: "FRO
 ';
 $string['placement'] = 'Placement';
 $string['pluginname'] = 'User tours';
+$string['previousstep'] = 'Previous';
 $string['resettouronpage'] = 'Reset user tour on this page';
 $string['right'] = 'Right';
 $string['select_block'] = 'Select a block';

admin/tool/usertours/templates/tourstep.mustache

@@ -58,9 +58,9 @@
     <div class="modal-body" data-placeholder="body">
     </div>
     <div class="modal-footer">
-      <button type="button" class="btn btn-secondary" data-role="previous" aria-label="{{# str }} previouspage, moodle {{/ str }}">{{# str }} previouspage, moodle {{/ str }}</button>
-      <button type="button" class="btn btn-primary" data-role="next" aria-label="{{# str }} nextpage, moodle {{/ str }}">{{# str }} nextpage, moodle {{/ str }}</button>
-      <button class="btn btn-secondary" data-role="end" aria-label="{{# str }} endtour, tool_usertours {{/ str }}"> {{# str }} endtour, tool_usertours {{/ str }} </button>
+      <button type="button" class="btn btn-secondary" data-role="previous">{{# str }} previousstep, tool_usertours {{/ str }}</button>
+      <button type="button" class="btn btn-primary" data-role="next">{{# str }} nextstep, tool_usertours {{/ str }}</button>
+      <button class="btn btn-secondary" data-role="end"> {{# str }} endtour, tool_usertours {{/ str }} </button>
     </div>
   </div>
 </div>