docs: fix typos and copy-paste errors in comments

[Avicennasis]

Summary

Fix doc comment issues across 5 files:

Typos:

• server → serve in ServeHTTP comments (generator.go, generator_singleton.go)
• Stray ] bracket in helper.go doc comment

Copy-paste errors:

• SetBasePath comment said "host info" — copy-pasted from SetHost, should say "base path"
• ReflectGoTypes comment said "controls JSON indentation" — copy-pasted from IndentJSON
• ServeHTTP in singleton referenced http.HandleFunc instead of http.Handler

Grammar:

• list all of paths object → list all path objects
• enable HTTP handler support CORS → enables HTTP handler to support CORS

Go doc convention:

• Updated doc comment verbs to third-person singular per Go convention (create → creates, set → sets, add → adds, return → returns)

No functional changes — comments only.