Bean and error message improvements

[MateuszKubuszok]

The goal of this PR is housekeeping things related to error messages:

• better suggestions for cases requiring .enableMethodAccessors
• better suggestions for cases requiring .enableInhertedAccessors
• providing errors informing about field name or subtype match ambiguity
• removing some cases of name conflict by considering only setName(..): Unit as setters and allowing e.g. setName(...): this.type setters as opt-in

TODO:

• improve error messages:
  • better ambiguous error messages
  • better error messages suggesting bean getters/setters
  • better error messages suggesting accessors
  • error messages suggesting inherited methods
• create ambiguous field names error message
  • there should be NO ambiguity if user provided explicit matching via override that came out so difficult do do it right and it generated so many weird cases that for now I decided to now deal with it at all - any ambiguity -> error or custom name comparator
  • that includes withFieldRenamed this came out to be impossible, so instead w provided a better error message
• create flag enableNonUnitSetters
  • create flag and its parser
  • create config entry for flag
  • read and store Setter returned type
  • use flag and returned type to steer the logic
• tests:
  • test error messages for var name + setter name ambiguity in target (?)
    • fix behavior mismatch between Scala 2 and 3 - vars in constructor Scala 2 code treates as accessors and Scala 3 as constructor vals, now both are treating them as constructor vals when it comes to extracting values
  • test error messages for fields which are ambiguous after providing custom comparators
  • test non-unit setters
  • test error messages for subtype names which are ambiguous after providing custom comparators
  • test error messages for Java enums names which are ambiguous after providing custom
    • fix behavior mismatch between Scala 2 and 3 - Java enums values in Scala 2 has all the same type so they generated the same fresh term names from their type
• mkdocs
  • non-unit setters
  • fields ambiguity resolution
  • subtype ambiguity resolution
  • breaking changes in setter resolution
  • update failed derivation messages in docs
• scaladocs

[codecov]

Codecov Report

Attention: Patch coverage is 96.33028% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 91.84%. Comparing base (1dc69eb) to head (a702482).

Files	Patch %	Lines
...er/rules/TransformProductToProductRuleModule.scala	91.48%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #485      +/-   ##
==========================================
+ Coverage   90.02%   91.84%   +1.81%     
==========================================
  Files         125      100      -25     
  Lines        4663     2354    -2309     
  Branches      393      228     -165     
==========================================
- Hits         4198     2162    -2036     
+ Misses        465      192     -273     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.