Support for Linters

[sbmueller]

Hi there!
I see many similar requests here that all circle around the same topic: Supporting non-LSP linters.
A linter is a static code analysis tool that in its simplest form reads a file from disk and outputs diagnostics on stdout:

$ linter my/file.cpp
my/file.cpp:28:1: Don't do this
my/file.cpp:32:10: Don't do that

There are a lot of linters that do not implement the LSP protocol, unfortunately. Similar plugins exist for other IDEs, e.g. here is a popular one for neovim.
I reckon the effort for this is manageable. Zed would need to invoke the linter and either provide the filepath of the current file or the buffer contents as stdin. Then, a regex can be used to parse the output that can be used to populate Zed's diagnostic table.

[mprz1024]

This is a no-brainer. There are a ton of tools different teams run on save as part of their toolchain, and it's surprising Zed can't take that into diagnostics. If everything must happen through LSP, why can't we have an empty LSP server we can configure to run these?