Fix regression in 6fbca01a2.
Also make it so the "reply" link automatically inserts the cursor into
the reply box. Do this for both forum posts and comments. Before it only
did this when quoting a post, not when creating a new post.
Add a 'Copy Link' action to forum posts and comments. This copies the
full link to the clipboard. The 'Copy ID' action copies just the DText
shortlink (comment #XXX or forum #XXX).
Add a Shortlink menu option to the comment menu. Clicking this will copy
a DText comment shortlink (e.g. `comment #12345`) to the clipboard. You
can middle-click or right-click the menu option to get the full URL.
The menu option is called Shortlink instead of `comment #1234` because
show the full comment ID in the menu makes the menu look too unbalanced.
Note that the `navigator.clipboard` API can only be used in a https://
environment. It won't work in non-HTTPS development environments. ngrok
can help with this.
