feat: add SuggestedFixes for --fix support

[raeperd]

Why

golangci-lint supports --fix to auto-fix linter issues, but recvcheck only reports diagnostics without suggested fixes. Users have to manually change value receivers to pointer receivers.

What

Attach analysis.SuggestedFix with TextEdits that insert * before value receiver type names. When golangci-lint --fix is used, value receivers are automatically converted to pointer receivers.

Changes

• Switch pass.Reportf → pass.Report(analysis.Diagnostic{...}) with SuggestedFixes
• Track value receiver *ast.Ident positions during AST walk
• Switch tests to analysistest.RunWithSuggestedFixes with .go.golden files

Summary by CodeRabbit

• New Features

  • Analyzer now provides automatic suggested fixes to convert non-pointer method receivers to pointer receivers, with text edits applied at the identifier positions.

• Tests

  • Updated test harness to verify suggested fixes alongside diagnostics.
  • Added comprehensive test fixtures covering various serialization patterns.

[coderabbitai]

Important

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 3472fb74-f79e-4bec-a319-49299e954455

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• ✅ Review completed - (🔄 Check again to review again)

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/suggested-fixes

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@analyzer.go`:
- Around line 105-112: The call pass.Pkg.Scope().Lookup(recv) can return nil and
calling .Pos() would panic; update the diagnostic creation in the block that
calls pass.Report so you first capture the result of
pass.Pkg.Scope().Lookup(recv) into a variable, check for nil, and use a safe
fallback position (for example token.NoPos or the position of the first related
method) when lookup is nil before passing Pos into analysis.Diagnostic; keep the
same Message and SuggestedFixes logic but supply the guarded position to avoid
nil dereference.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 833209dd-ae10-4d4a-9520-d22f79cd0e2e

📥 Commits

Reviewing files that changed from the base of the PR and between 8ade7fa and c0ef36c.

📒 Files selected for processing (9)

• analyzer.go
• analyzer_test.go
• testdata/src/basic/rpc.go.golden
• testdata/src/disablebuiltin/binary.go.golden
• testdata/src/disablebuiltin/gob.go.golden
• testdata/src/disablebuiltin/json.go.golden
• testdata/src/disablebuiltin/text.go.golden
• testdata/src/disablebuiltin/xml.go.golden
• testdata/src/disablebuiltin/yaml.go.golden