Provide full type definitions

E.g., I'd like to know what telemetry levels there are or what possible messages are sent via didChangeStatus`.

An exhaustive overview such as type definition file would help me catch all the cases without too much experimenting.

No file or entry point is named. Start by inspecting the repository for the language-server protocol definitions and the sources of telemetry levels and didChangeStatus messages; done means providing an exhaustive type-definition overview covering the possible values and messages.

索引モデルが issue の本文から書いたものです。