Scala portable full changelog

Highlights of the release:
Support records in JavaParsers
Port JVM backend refactor from Scala 2

Highlights of the release:
Make truncation by characters in REPL configurable #16167
New (experimental for now) lazy vals implementation #15296
Make coverage instrumentation more robust
Resolve overloading: keep track of prefix and indices of all default getters
Let accessors inherit @experimental annotations from accessed symbols

Highlights:
TASTy Reader support for Scala 3.0.0 (#9617 by @bishabosha)
The splain compiler plugin by @tek was integrated into the compiler, available with the -Vimplicits and -Vtype-diffs flags (#7785)
Escaped double quotes now work as expected in string interpolations, both s""" and s"$"" (#8830 by @eed3si9n and #9536 by @martijnhoekstra)
Other Changes:
Optimized BigInt implementation (#9628) by @denisrosset
Support JDK15 text blocks in Java parser (#9548) by @harpocrates
Stricter override checking for protected Scala members which override Java members (#9525) by @kynthus
Check private[this] members in override checking (#9542)
More accurate outer checks in patterns (#9504)
Allow renaming imports from _root_ (#9482) by @som-snytt
Make more annotations extend ConstantAnnotation (9336) by @BalmungSan
A number of syntax changes were added to simplify cross-building between Scala 2 and 3
Don't error (only warn) on symbol literals under -Xsource:3 (#9602)

Highlights:
TASTy reader: add support for Scala 3.0.0-RC1
Allow name-based extractors to be irrefutable
JDK 16 and 17 support in the optimizer

This release has:
A brand-new Vector implementation
Configurable warnings

This is primarily a bug fix release that fixes several regressions in 2.13.0.

The changes include:
Several issues in the collections library were resolved, most notably equality on ranges (SI-8738).
The optimizer no longer eliminates division instructions that may throw an ArithmeticException (SI-7607).
The -Xlint compiler flag is now parameterized by individual warnings. This is intended to replace the -Ywarn-... options, for instance, -Xlint:nullary-unit is equivalent to -Ywarn-nullary-unit. Run scalac -Xlint:help to see all available options.
TypeTags and Exprs are now serializable (SI-5919).
Compared to 2.11.1, this release resolves 49 issues. We reviewed and merged 70 pull requests.