VSCode: Add configuration option to only show diagnostics for open files

[LouieK22]

Should there be a configuration option to show diagnostics for open files, or should this become the default behavior, which would be in line with other linting extension behavior?

[Kampfkarren]

How do other extensions solve these problems?

[JohnnyMorganz]

Both eslint and rust-analyzer clear the diagnostics of a file once it has been closed. It does mean that you may forget about some of the diagnostics that pop up, so I imagine a checkbox setting to toggle this would suit everyone.

EDIT: maybe even breaking it down into an option which clears only warnings, and forcing errors to remain persist? So you can still catch breaking bugs.

I know this is a common thing when people open up vendored code, and then it clutters the problems panel