Fix undisruptive formatting issues (#1848)

* Skip unparsable pylib files with black

This was causing black to return a non-zero code, preventing the
subsequent isort from running.

* Organise imports on save

.vscode/settings.json

@@ -1,5 +1,8 @@
 {
     "editor.formatOnSave": true,
+    "editor.codeActionsOnSave": {
+        "source.organizeImports": true
+    },
     "files.watcherExclude": {
         "**/.git/objects/**": true,
         "**/.git/subtree-cache/**": true,

pylib/tests/run_format.py

@@ -39,7 +39,7 @@ if __name__ == "__main__":
             "anki",
             "tests",
             "tools",
-            "--exclude=_pb2|buildinfo|_gen",
+            "--exclude=_pb2|buildinfo|_gen|_backend/generated|fluent",
         ]
         + args,
         check=False,