Add a description on what groups do

src/components/settings_modal/tabs/profile_tab.js

@@ -120,8 +120,11 @@ const ProfileTab = {
       const src = this.$store.state.users.currentUser.cover_photo
       return (!src) ? this.defaultBanner : src
     },
+    groupActorAvailable () {
+      return this.$store.state.instance.groupActorAvailable
+    },
     availableActorTypes () {
-      return this.$store.state.instance.groupActorAvailable ? ['Person', 'Service', 'Group'] : ['Person', 'Service']
+      return this.groupActorAvailable ? ['Person', 'Service', 'Group'] : ['Person', 'Service']
     }
   },
   methods: {

src/components/settings_modal/tabs/profile_tab.vue

@@ -122,6 +122,11 @@
           </Select>
         </label>
       </p>
+      <div v-if="groupActorAvailable">
+        <small>
+          {{ $t('settings.actor_type_description') }}
+        </small>
+      </div>
       <p>
         <interface-language-switcher
           :prompt-text="$t('settings.email_language')"

src/i18n/en.json

@@ -360,6 +360,7 @@
     "primary_language": "Primary language:",
     "fallback_language": "Fallback language {index}:",
     "actor_type": "This account is:",
+    "actor_type_description": "Marking your account as a group will make it automatically repeat statuses that mention it.",
     "actor_type_Person": "a normal user",
     "actor_type_Service": "a bot",
     "actor_type_Group": "a group",