vscode-go readability improvement

[h9jiang]

vscode-go carries different style guides maybe some of the practice was considered best at that time but no longer considered best now.

To make the repo easier to maintain, I hope we can stick to Google Typescript Style Guide. The same style guide should be added to contributing.md to enforce future code changes proposed by community contributors.

In the meantime, we will also gradually make readability improvement while investigating issue reported or implementing feature requests.

All readability improvement CL will reference this git issue in commit message.

cc @madelinekalil @findleyr

[gopherbot]

Change https://go.dev/cl/654215 mentions this issue: extension/src: add separator in command go.environment.choose

[gopherbot]

Change https://go.dev/cl/654435 mentions this issue: extension/src/language: remove wrapper interface over LanguageServerConfig

[gopherbot]

Change https://go.dev/cl/660055 mentions this issue: extension/src: change function doc using JSDoc

[gopherbot]

Change https://go.dev/cl/660095 mentions this issue: extension/src: rename telemetry state starting to running

[gopherbot]

Change https://go.dev/cl/660396 mentions this issue: extension/src: remove sampling and machine ID from telemetry service

[gopherbot]

Change https://go.dev/cl/661056 mentions this issue: extension/src: use enum for telemetry key