Disable mypy's misc errors completely

This fixes "Decorated property not supported" errors for the time being without
hopefully many downsides. The impact is hard to measure as the list of misc errors
is not to be found.

This should be revisited if/when python/mypy#1362 gets solved.

pyproject.toml

@@ -105,8 +105,9 @@ exclude_lines = [
   "def __repr__"
 ]
 
-[tool.check-manifest]
-ignore = ["devtools/*"]
+[tool.mypy]
+# disables "Decorated property not supported", see https://github.com/python/mypy/issues/1362
+disable_error_code = "misc"
 
 [build-system]
 requires = ["poetry-core"]