ci: Improve mypy output

- Set MYPY_FORCE_TERMINAL_WIDTH to get 180-column output (rather than 80), so
  that error messages fit on one line.
- Set MYPY_FORCE_COLOR to get colored output
- Adjust problemmatcher regex accordingly

.github/workflows/ci.yml

@@ -2,6 +2,8 @@ name: CI
 on: [push, pull_request]
 env:
   PY_COLORS: "1"
+  MYPY_FORCE_TERMINAL_WIDTH: "180"
+  MYPY_FORCE_COLOR: "1"
 
 jobs:
   linters:

scripts/dev/ci/problemmatchers.py

@@ -89,7 +89,7 @@ MATCHERS = {
         {
             "pattern": [
                 {
-                    "regexp": r"^([^:]+):(\d+): ([^:]+): (.*)  \[(.*)\]$",
+                    "regexp": r"^([^:]+):(\d+): \033\[1m\033\[31m([^:]+):\033\[m (.*)  \033\[m\033\[33m\[(.*)\]\033\[m$",
                     "file": 1,
                     "line": 2,
                     "severity": 3,

tox.ini

@@ -197,7 +197,7 @@ commands = bash scripts/dev/run_shellcheck.sh {posargs}
 [testenv:mypy]
 basepython = {env:PYTHON:python3}
 pip_version = pip
-passenv = TERM
+passenv = TERM MYPY_FORCE_TERMINAL_WIDTH MYPY_FORCE_COLOR
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/misc/requirements/requirements-dev.txt