Hint for enter key in post status form

src/components/post_status_form/post_status_form.scss

@@ -16,7 +16,7 @@
   .form-bottom {
     display: flex;
     justify-content: space-between;
-    padding: 0.5em;
+    padding: 0.5em 0.5em 0.25em;
     height: 2.5em;
 
     .post-button-group {
@@ -210,6 +210,13 @@
     flex-direction: column;
   }
 
+  .keyboard-enter-hint {
+    text-align: right;
+    margin-right: 1em;
+    line-height: 1;
+    margin-bottom: 0.5em;
+  }
+
   textarea.input.form-post-body {
     // TODO: make a resizable textarea component?
     box-sizing: content-box; // needed for easier computation of dynamic size

src/components/post_status_form/post_status_form.vue

@@ -381,6 +381,14 @@
           </Popover>
         </div>
       </div>
+      <small class="keyboard-enter-hint faint">
+        <i v-if="submitOnEnter">
+          {{ $t('post_status.enter_submits') }}
+        </i>
+        <i v-else>
+          {{ $t('post_status.enter_newline') }}
+        </i>
+      </small>
       <div
         v-show="showDropIcon !== 'hide'"
         :style="{ animation: showDropIcon === 'show' ? 'fade-in 0.25s' : 'fade-out 0.5s' }"