Square brackets in rewritten output

I'm rewriting a field as a link to /foo/[nid]?gids_group[]=[gid]

The square brackets were being encoded and not working properly, so I took the advice from the interface text "If you would like to have the characters %5B and %5D please use the html entity codes \'%5B\' or \'%5D\'". This advice did not work, as these characters ended up encoded as %255B and %255D. However, using [ and ] did the trick. This is different than what was reported for D6 in #567918: Rewrite field using with non-tokens in square brackets.