Remove [ and ] from the regexp used by the URL filter.
Remove [ and ] from the regexp used by the URL filter.

These characters are rarely used in URLs, and including them leads to
mislinkifying when editing various formats, such as wiki markup formats that
use [] around links.

xavidotron/etherpad-lite,xavidotron/etherpad-lite,xavidotron/etherpad-lite,xavidotron/etherpad-lite