* Relax tag validation restriction to permit alphanumeric strings
Non-word symbols like musical notes are still blocked, but most
languages should work.
* Handle redirect after tag edit
The URI.parse(tag.name) was not updated in #13720
Move reused logic into tag_path method in URL module.
* FactoryBot generated tags are non-ascii
This should help expose any cases where we're mistakenly counting on
ascii-only content in tags by causing all generated tags without a
specified name to be of the form `tag你好#{n}` instead of `tag#{n}`.
* Revert "FactoryBot generated tags are non-ascii"
This reverts commit ed1035cd1e91619b2c1599e521b6ddf962c97f80.
It was useful to see how many places the path knowledge is in the
tests (a lot of requests have GET /t/tag.name and need to have GET
URL.tag_path instead).
https://app.travis-ci.com/github/forem/forem/builds/237542600 has the
results.
Reverting because those test-side changes seem like a secondary
concern to the change in this PR (I'll file a follow on issue)
21e9966ccb