Change shortcut for submitting uploads from Enter to Ctrl+Enter

[evazion]

Pressing Enter in the tag edit box currently either submits the upload or saves the tag edit. This should be removed. You should have to press Ctrl+Enter instead. Ctrl+Enter already works and is already used sitewide.

There are too many cases of users accidentally submitting uploads before they're ready. This is a very easy mistake to make, since the Enter key is used to select tags in autocomplete. This has been a problem for years.

There will be a transition period to let users get used to the change:

• First a "Press Ctrl+Enter to submit" message will be added beneath the tag box, to let people know about the new shortcut.
• Later on, the Enter key will still work but popup a message saying that Ctrl+Enter should be used instead.
• Finally, the Enter key will be removed and you'll have to use Ctrl+Enter.