change wording on shared runners limits setting description

app/views/admin/application_settings/_form.html.haml

@@ -220,7 +220,8 @@
       .col-sm-10
         = f.number_field :shared_runners_minutes, class: 'form-control'
         .help-block
-          Set the maximum number of minutes that a group can use shared runners in a one month period. 0 for unlimited.
+          Set the maximum number of build minutes that a group can use on shared runners per month.
+          0 for unlimited.
           = link_to "(?)", help_page_path("user/admin_area/settings/continuous_integration", anchor: "shared-runners-minutes")
     .form-group
       = f.label :shared_runners_text, class: 'control-label col-sm-2'

app/views/groups/_shared_runners_minutes_setting.html.haml

@@ -5,7 +5,7 @@
     .col-sm-10
       = f.number_field :shared_runners_minutes_limit, class: 'form-control', min: 0
       %span.help-block#shared_runners_minutes_limit_help_block
-        Set the maximum number of minutes that a group can use shared runners in a one month period.
+        Set the maximum number of build minutes that a group can use on shared runners per month.
         Set 0 for unlimited.
         Set empty to inherit global setting of #{current_application_settings.shared_runners_minutes}.
         = link_to icon('question-circle'), help_page_path("user/admin_area/settings/continuous_integration", anchor: "shared-runners-minutes")