Missing tests for +/# with pct-encoded characters

[castaway]

https://tools.ietf.org/html/rfc6570#section-3.2.3 -

Reserved expansion, as indicated by the plus ("+") operator for Level 2 and above templates, is identical to simple string expansion except that the substituted values may also contain pct-encoded triplets and characters in the reserved set.

I just reported this here: bricas/uri-template#7 - and then realised the test suite doesn't cover them either (no explicit examples in the RFC). I will create some.