Fix paragraph formatting in the reply-to box (#1257)

This CSS was accidentally deleted back when I was implementing `Article`
support. Now when you reply to something that has paragraph breaks, the paragraph
breaks render correctly.

Fixes #1241

app/javascript/styles/mastodon/components.scss

@@ -925,6 +925,16 @@
     }
   }
 
+  p {
+    margin-bottom: 1em;
+    white-space: pre-wrap;
+    unicode-bidi: plaintext;
+
+    &:last-child {
+      margin-bottom: 0;
+    }
+  }
+
   a {
     color: $secondary-text-color;
     text-decoration: underline;