Clean up the form-related template tags/filters and add unit tests.

Review Request #9619 — Created Feb. 10, 2018 and submitted — Latest diff uploaded

Information

Djblets
master
72ea639...

Reviewers

The form-related template tags and filters in
djblets.util.templatetags.djblets_forms are pretty old, and have some
outdated logic and almost no test coverage or documentation. This change
modernizes them, fixing them up to meet current standards and to have
comprehensive test coverage.

Unit tests pass.