Lift Scala Settings from experimental to stabilized

[rochala]

Fixes: #19693

This is the tracking list from the issue and the status of migraton.

• lift to -X
  • -Yresolve-term-conflict
  • -YnoGenericSig
  • -Ydumpclasses
  • -YjarCompressionLevel
  • -YkindProjector
  • -YdropComments
  • -YcookComments
  • -YreadComments
  • -YnoDecodeStacktraces
  • -YnoEnrichErrorMessages
  • -YdebugMacros
  • -YjavaTasty- deprecate in 3.7.0
  • -YjavaTastyOutput- deprecate in 3.7.0
  • -YallowOutlineFromTasty- deprecate in 3.7.0
• lift to -W
  • -Wsafe-init
• to be removed
  • --Yforce-inline-while-typing // Note: this was already removed by 05eb7f7
• TBD
  • -YfromTastyIgnoreList // this flag was not decided
  • -YoutputOnlyTasty

I suppose 2 last flags that have to be decided are maintained by @bishabosha
Do you know their status ?

Other than that, this PR implemented a deprecation mechanism for the future e.g.

Deprecation(
  msg = "message",
  replacedBy = Some("newMessage"),
)

EDIT:
As it was decided, options responsible for pipelining will be retained until 3.7.0.
The code is commented and following PR which will deprecate them will be created after merging this one.

EDIT2:
-Xlint is a very problematic flag. It was added into the compiler in 3.4 bypassing argument verification. Then in the future, when it was deprecated in favour of -Wshadow we couldn't exactly map them 1-1, and it was deprecated in following way:

• Scala 2: -Xlint is valid flag,
• Scala pre 3.4: -Xlint was skipped as it was not implemented,
• Scala post 3.4 pre flag refactor: -Xlint was implemented allowing for all, private-shadow and type-parameter-shadow options. It also bypassed argument verification allowing standalone -Xlint to be ignored, not reported as error,
• Scala post 3.4 post flag refactor: This flag was then deprecated in favour of -Wshadow. We didn't want to commit this mistake again and allow standalone -Wshadow thus when it was deprecated, we didn't handle it as we should (deprecated option should trigger replacement when possible).

That's why I'm retaining the previous behaviour of -Xlint. It will be removed in the future versions as it is already deprecated.

[Gedochao]

This has been decided to be included in the 3.5.0 release.

Note: The following flags will have to not print the deprecation warning, despite them being lifted to -X. The reason for this is that they are currently hardcoded in SBT, so we need to give users time to upgrade.

• -YjavaTasty
• -YjavaTastyOutput
• -YallowOutlineFromTast

The deprecation message will be added in a future minor release (no earlier than 3.7.x), and we will remove the old syntax no later than before the next LTS version (>3.3.x).

[nicolasstucki]

We should consider removing -Youtput-only-tasty. We do not use it internally anymore and no library should ever publish a JAR that only contains TASTy (except for the Scala 2 TASTy library).

[rochala]

Don't auto merge this, we're still waiting for community build (full community build) to finish 😅