Previously I had misunderstanding of how to use vscode-uri (#42658),
and recently we have #55891 and #56104.

We need some documentation for Uri.parse and Uri.file to know

• Which one to use?
• What kind of input do they take? For example, on Windows, do Uri.file take /c:/foo, or C:\foo, or /C:\foo? On macOS/Linux, does it take relative paths or only absolute paths?

also for path and fsPath:

• What's the expected output for each in all platforms?
• What's the transformation that happens to the original URI? For example, does drive letter change cases on Windows? Does it normalize slashes to forward slashes?

They should be in JSDocs so it shows up in IntelliSense. Would be great to have them in the vscode-uri readme too.