791cb87cdf
feat: Allow viewing the full compiler diagnostic in a readonly textview ![Code_y1qrash9gg](https://user-images.githubusercontent.com/3757771/202780459-f751f65d-2b1b-4dc3-9685-100d65ebf6a0.gif) Also adds a VSCode only config that replaces the split diagnostic message with the first relevant part of the diagnostic output ![Code_7k4qsMkx5e](https://user-images.githubusercontent.com/3757771/202780346-cf9137d9-eb77-46b7-aed6-c73a2e41e1c7.png) This only affects diagnostics generated by primary spans and has no effect on other clients than VSCode. Fixes https://github.com/rust-lang/rust-analyzer/issues/13574