Fix TPAC account preferences

Clean up a few problems in the TPAC "My Account" preferences area:

1. Add a missing </form> closing element, which was preventing any
   submitted changes from actually being posted to the correct URL
   (thus preventing most account preference changes such as
   notifications).
2. Remove trailing semicolon from several generated <option> elements
   for cleaner HTML.
3. Make the aria-label for the element translatable.

As we're touching a majority of the lines in the section and the lines
do not follow normal whitespace standards (mixed tabs, inconsistent
indentation, etc), clean up the whitespace.

Also turn one HTML comment into a Template::Toolkit comment.

Signed-off-by: Dan Scott <dscott@laurentian.ca>
Signed-off-by: Dan Wells <dbw2@calvin.edu>