Correct square bracket handling in URL netloc

[mjpieters]

• The human representation of usernames and passwords should percent-encode square brackets.
• Clean up the test suite to remove tests that use invalid hostnames (square brackets in a host name must only be used for IPv6 addresses).
• Rename the remaining test using IPvFuture address syntax to make this explicit.
• Drop a test for IPv6 addresses with a zone id; zone id support is controversial and expilictly excluded from the WHATWG URL standard. Zone ids without percent characters in their name continue to work as long as urllib.parse.urlsplit() accepts them but this is not something that yarl.URL() needs to support explicitly.

Fixes #876

[mjpieters]

Note that the issues raised by #876 are not really visible in the current test suite. If #881 lands first, then this PR should will clear the test errors shown there, or we could wait for Github to roll out Python 3.11.4, at which point the test suite will start to fail too unless this PR is merged. 😄

[codecov]

Codecov Report

Merging #882 (5c977b5) into master (8451c5b) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #882   +/-   ##
=======================================
  Coverage   99.74%   99.74%           
=======================================
  Files           4        4           
  Lines         772      772           
  Branches      219      219           
=======================================
  Hits          770      770           
  Misses          2        2           

Flag	Coverage Δ
unit	99.61% <100.00%> (ø)

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Impacted Files	Coverage Δ
yarl/_url.py	99.66% <100.00%> (ø)

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[mjpieters]

#881 has been merged and this PR has been rebased; all tests now pass.

[mjpieters]

@webknjaz, @asvetlov Any opinions on this PR? Otherwise I'll just merge it soon, as 3.11.4 is now out and so certain yarl features look broken on that release.

[webknjaz]

I don't have an opinion on this but it's probably fine, except for that typo.

[webknjaz]

Talking about releases, I'm working on a PEP 517-driven packaging remake, hopefully will finish it today..

[webknjaz]

• Drop a test for IPv6 addresses with a zone id; zone id support is controversial and expilictly excluded from the WHATWG URL standard. Zone ids without percent characters in their name continue to work as long as urllib.parse.urlsplit() accepts them but this is not something that yarl.URL() needs to support explicitly.

@mjpieters this is how I feel this should be supported FYI: #998