added distributeIdentityLaw

[kailuowang]

No description provided.

[kailuowang]

@coltfred WDYT?

[codecov-io]

Codecov Report

Merging #2097 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2097      +/-   ##
==========================================
+ Coverage   94.65%   94.66%   +<.01%     
==========================================
  Files         322      322              
  Lines        5449     5451       +2     
  Branches      215      215              
==========================================
+ Hits         5158     5160       +2     
  Misses        291      291

Impacted Files	Coverage Δ
...ws/src/main/scala/cats/laws/DistributiveLaws.scala	100% <100%> (ø)	⬆️
...scala/cats/laws/discipline/DistributiveTests.scala	100% <100%> (ø)	⬆️

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[coltfred]

@kailuowang I think that looks reasonable to me. We could remove cosequenceIdentity since cosequence is just distribute(identity). Maybe it's fine to leave it as it ensures they're consistent. Sorry I didn't add this in the first place.

[kailuowang]

@coltfred no worries.
I thought about removing cosequenceIdentity, but as you suggested it's verifying the consistency between the two.

[ceedubs]

Thanks!