Merge #408
408: vscode problem matcher improvements r=matklad a=vemoo
The problem matcher wasn't working properly and looking at the rustc errors i realized it could be simplified.
I also added a new problem matcher that can be used with https://github.com/passcod/cargo-watch to get the errors in the editor on save. To use it one can create a tasks.json file with:
```json
{
"version": "2.0.0",
"tasks": [
{
"type": "shell",
"label": "cargo watch",
"command": "cargo",
"isBackground": true,
"args": [
"watch",
"-c"
],
"problemMatcher": [
"$rustc-watch"
]
}
]
}
```
I initially implemented it like this: https://github.com/rust-analyzer/rust-analyzer/commit/
cff9f62d321a90c45e622f5304e60a248cbcf4f2 but i think there's a bug in vscode so i worked around it by copying the pattern for both problem matchers. The first commit can be used if https://github.com/Microsoft/vscode/pull/65840 is merged.
Co-authored-by: Bernardo <berublan@gmail.com>