If I'm replying to a post in Klingon, chances are I'm going to write in
Klingon. This reduces friction for properly marking post language in a
conversation.
This fixes random actions being triggered by the enter key while the
subject field is focused.
When pressing enter, the browser simulates a click on the first "submit"
button it finds in the form.
A submit button is a button without `type="button"` set.
Remediate this by setting the type attribute on all but the "Post"
button.
Additionally, inhibit the enter key in the subject field (ctrl+enter
still works).
