Add frozenset type

[dswij]

Part of #9

Mostly taken from Set since both Set and FrozenSet are almost identical from pydantic POV.

[codecov]

Codecov Report

Merging #86 (b432dab) into main (77b7ae6) will increase coverage by 0.10%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #86      +/-   ##
==========================================
+ Coverage   94.68%   94.78%   +0.10%     
==========================================
  Files          39       40       +1     
  Lines        3404     3454      +50     
  Branches       26       27       +1     
==========================================
+ Hits         3223     3274      +51     
+ Misses        181      180       -1     

Impacted Files	Coverage Δ
src/errors/kinds.rs	100.00% <ø> (ø)
src/validators/set.rs	97.91% <ø> (-0.48%)	⬇️
src/validators/tuple.rs	98.48% <ø> (-0.15%)	⬇️
pydantic_core/_types.py	100.00% <100.00%> (ø)
src/input/input_abstract.rs	100.00% <100.00%> (ø)
src/input/input_json.rs	97.18% <100.00%> (+0.10%)	⬆️
src/input/input_python.rs	93.65% <100.00%> (+0.37%)	⬆️
src/validators/frozenset.rs	100.00% <100.00%> (ø)
src/validators/list.rs	75.80% <100.00%> (ø)
src/validators/mod.rs	98.31% <100.00%> (+0.01%)	⬆️
... and 1 more

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[samuelcolvin]

Just a few things, otherwise this is looking great.

[samuelcolvin]

looks like tests are not running because of conflicts.

[samuelcolvin]

looks like tests are not running because of conflicts.

[samuelcolvin]

thanks so much, this is great.