Add flatMapToMap diagnostic

[mattiamanzati]

Summary

• add the suggestion-level flatMapToMap style diagnostic for Effect v3 and v4 piping flows
• provide a quick fix that replaces Effect.flatMap with Effect.map and unwraps Effect.succeed
• add a shared TypeParser.functionExpression parser and reuse it in catchAllToMapError
• document the diagnostic and add generated metadata, schema, completion, fixture, and snapshot coverage

Example

Effect.succeed(1).pipe(
  Effect.flatMap((value) => Effect.succeed(value + 1))
)

becomes:

Effect.succeed(1).pipe(
  Effect.map((value) => value + 1)
)

Validation

• pnpm codegen
• pnpm lint-fix
• pnpm check
• pnpm test
• pnpm test:v4

[changeset-bot]

🦋 Changeset detected

Latest commit: f153304

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@effect/language-service	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR