Improve messaging of CA1861

[buyaa-n]

Updating messaging of CA1861 to apply the suggestion if the array argument is not mutated within the invoked method

Related to dotnet/runtime#86229 (comment) and dotnet/runtime#86414

[danmoseley]

Worth also adding the caveat -- "and if the called method is called repeatedly" or something ?

[buyaa-n]

the called method is called repeatedly

Updated message: Prefer 'static readonly' fields over constant array arguments if the called method is not mutating the passed array and it is called repeatedly

Description: Constant arrays passed as arguments are not reused when called repeatedly, which implies a new array is created each time. Consider extracting them to 'static readonly' fields to improve performance if the passed array is not mutated within the called method.

[codecov]

Codecov Report

Merging #6642 (26abac4) into main (c2fd19b) will decrease coverage by 0.01%.
The diff coverage is n/a.

❗ Current head 26abac4 differs from pull request most recent head d233646. Consider uploading reports for the commit d233646 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6642      +/-   ##
==========================================
- Coverage   96.40%   96.40%   -0.01%     
==========================================
  Files        1377     1377              
  Lines      322008   322008              
  Branches    10434    10434              
==========================================
- Hits       310438   310429       -9     
- Misses       9081     9089       +8     
- Partials     2489     2490       +1