Use FAB button with tooltip

aleksis/apps/alsijil/frontend/components/coursebook/absences/AbsenceCreationDialog.vue

@@ -9,6 +9,7 @@
           'd-none': !checkPermission('alsijil.view_register_absence_rule'),
         }"
         icon-text="$plus"
+        i18n-key="alsijil.coursebook.absences.button"
       >
         <v-icon>$plus</v-icon>
       </fab-button>

aleksis/apps/alsijil/frontend/messages/en.json

@@ -79,6 +79,7 @@
       "no_results": "No search results for {search}",
       "absences": {
         "title": "Capture absences",
+        "button": "Register absences",
         "summary": "Summary",
         "lessons": "No lessons | 1 lesson | {count} lessons",
         "success": "The absences were captured successfully.",