Remove broken gh-pages submodule

[wthomason-bdai]

This PR removes the gh-pages directory, which appears to have been set up as a submodule, but has no definition in a .gitmodules file (as no such file is present). This misconfiguration causes problems adding spatialmath-python as a dependency to other projects using uv. If I'm wrong about gh-pages being necessary to keep around (e.g., if it somehow triggers the creation of a Github Page for the project?), then we'll need to find a different solution.

[myeatman-bdai]

Yeah, it looks like this used when generating documentation web pages, here

[wthomason-bdai]

@myeatman-bdai Does that actually require the pseudo-submodule, though? Won't that command create the directory if missing?

[wthomason-bdai]

(or, if not, we could add a mkdir -p gh-pages to that CI block?)

[myeatman-bdai]

I don't know much about gh-pages but I think that the git commands

git add .
git commit -m "Update documentation" -a || true

won't work.

[wthomason-bdai]

Shouldn't https://github.com/bdaiinstitute/spatialmath-python/blob/99fd55b8fefa3113fc7a6ea99e5b0232adb541a6/.github/workflows/sphinx.yml#L32-L33 (or optionally the additional mkdir line before those two) make it work?

[myeatman-bdai]

oh, you're right. Derp.

[myeatman-bdai]

Lets just merge this and see if the documentation generation still works.

[myeatman-bdai]

👍

[myeatman-bdai]

Per this yet to be merged PR #162, the sphinx automation is broken with or without this small changes, so we're going ahead and merging.