Enhance the compiler to produce a FS0750 error on let! or use! outside a CE

[evgTSV]

Description

As the active pattern LetOrUse was unreachable due to the common SynExpr.LetOrUse _, I've put the active pattern above SynExpr.LetOrUse _

Fixes #19345

Checklist

• Test cases added

• Performance benchmarks added in case of performance changes

• Release notes entry updated:

  Please make sure to add an entry with short succinct description of the change as well as link to this pull request to the respective release notes file, if applicable.

  Release notes files:

  • If anything under src/Compiler has been changed, please make sure to make an entry in docs/release-notes/.FSharp.Compiler.Service/<version>.md, where <version> is usually "highest" one, e.g. 42.8.200
  • If language feature was added (i.e. LanguageFeatures.fsi was changed), please add it to docs/release-notes/.Language/preview.md
  • If a change to FSharp.Core was made, please make sure to edit docs/release-notes/.FSharp.Core/<version>.md where version is "highest" one, e.g. 8.0.200.

  Information about the release notes entries format can be found in the documentation.
  Example:

  • More inlines for Result module. (PR #16106)
  • Correctly handle assembly imports with public key token of 0 length. (Issue #16359, PR #16363)
    *while! (Language suggestion #1038, PR #14238)

  If you believe that release notes are not necessary for this PR, please add NO_RELEASE_NOTES label to the pull request.

[github-actions]

❗ Release notes required

---

✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
src/Compiler	docs/release-notes/.FSharp.Compiler.Service/10.0.300.md

[vzarytovskii]

Release notes should go to 10.0.300, not 9.0.200

[evgTSV]

Release notes should go to 10.0.300, not 9.0.200

Yeah, I got it

Erroneously approved

[auduchinok]

Thanks!

[evgTSV]

I have to fix tests. Besides, I found that a case where let! is used together with and! doesn't trigger any errors.

[auduchinok]

This is great, thank you!