Update golangci-lint, fix issues, modernize

[jakebailey]

Updates the version, fixes or silences existing issues, then also enables the modernize fixes and fixes them except for the small number of cases I would like to ignore.

[jakebailey]

This func arguably shouldn't exist but that's larger diff.

[Copilot]

Pull Request Overview

This PR modernizes the codebase by adopting newer Go standard library features and patterns introduced in recent Go versions (primarily Go 1.23+). The changes leverage built-in optimizations and cleaner APIs.

Key changes:

• Adopts sync.WaitGroup.Go() method introduced in Go 1.23 to simplify goroutine spawning patterns
• Uses strings.Builder for efficient string concatenation instead of repeated string concatenation operations
• Replaces manual loops with standard library functions like slices.Contains(), slices.ContainsFunc(), maps.Copy(), and strings.CutPrefix/CutSuffix()
• Migrates to strings.SplitSeq() for iterator-based string splitting
• Simplifies type checking with reflect.TypeFor[T]()
• Replaces interface{} with any alias for consistency
• Updates golangci-lint version and enables the modernize linter

Reviewed Changes

Copilot reviewed 30 out of 30 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
.golangci.yml	Enables the modernize linter to enforce modern Go patterns
.custom-gcl.yml	Updates golangci-lint version from v2.5.0 to v2.6.0
internal/vfs/vfstest/vfstest_test.go	Adopts WaitGroup.Go() but missing wg.Wait() call
internal/tsoptions/tsconfigparsing_test.go	Uses maps.Copy() for map copying
internal/tsoptions/tsconfigparsing.go	Replaces runtime type check with compile-time type constant
internal/transformers/estransforms/objectrestspread.go	Uses slices.ContainsFunc() for cleaner iteration
internal/testutil/tsbaseline/error_baseline.go	Adopts strings.SplitSeq() iterator pattern with impossible condition bug
internal/testutil/harnessutil/harnessutil.go	Uses strings.CutPrefix/CutSuffix() for cleaner string trimming
internal/scanner/scanner.go	Migrates to strings.Builder for efficient string building
internal/project/background/queue.go	Adopts WaitGroup.Go() method
internal/project/ata/validatepackagename_test.go	Adds linter exception for intentional string concatenation in test
internal/parser/parser.go	Simplifies range loop with modern syntax
internal/module/resolver_test.go	Adopts WaitGroup.Go() method
internal/ls/signaturehelp.go	Removes custom containsNode() in favor of slices.Contains()
internal/ls/lsutil/userpreferences.go	Replaces interface{} with any alias
internal/ls/completions.go	Uses strings.CutPrefix() and strings.Builder
internal/glob/glob.go	Replaces interface{} with any alias
internal/fourslash/test_parser.go	Replaces interface{} with any alias
internal/fourslash/fourslash.go	Uses slices.Contains() for cleaner iteration
internal/fourslash/baselineutil.go	Replaces interface{} with any alias
internal/execute/tsctests/runner.go	Adds linter exception for intentional string concatenation
internal/core/workgroup.go	Adopts WaitGroup.Go() method
internal/core/core.go	Simplifies conditional logic with max() and adds linter exception
internal/compiler/projectreferenceparser.go	Uses maps.Copy() for map copying
internal/compiler/fileloader.go	Migrates to strings.Builder for efficient string building
internal/checker/nodebuilderimpl.go	Uses slices.Contains() for cleaner iteration
internal/checker/mapper.go	Uses slices.Contains() for cleaner iteration
internal/checker/grammarchecks.go	Adds linter exception to preserve existing loop pattern
internal/binder/binder.go	Adds linter exception to preserve existing loop pattern
internal/ast/ast.go	Adds linter exception to preserve existing loop pattern