Docs: fix old docs still being populated (#30825)

* fix push

* also remove cached files

* fix readme

* add readme

* remove that wip submodule
old-commit-hash: abe4780fdb

.github/workflows/docs.yaml

@@ -50,9 +50,10 @@ jobs:
         cd openpilot-docs
 
         git checkout --orphan tmp
-        git rm -rf --cached .
+        git rm -rf .
 
         cp -r ../build/docs/html/ docs/
+        cp -r ../docs/README.md .
         touch docs/.nojekyll
         echo -n docs.comma.ai > docs/CNAME
         git add -f .

docs/README.md

@@ -0,0 +1,3 @@
+# openpilot-docs
+
+These docs are autogenerated from [this folder](https://github.com/commaai/openpilot/tree/master/docs) in the main openpilot repository.