Merge #5896: fix: drop symlinks in immer subtree

c09981d8ad fix: drop symlinks in immer subtree (pasta)

Pull request description:

  ## Issue being fixed or feature implemented
  I've been playing around recently with the `github-merge.py` script recently; and while I've been able to create merges with it (see 73c90c8370 and 10ddf62dfb) it complains / refuses to trivially work with symlinks. I haven't been able to figure out exactly why it doesn't want symlinks, but I think it's related to the sha512sum hash that gets created.

  I'm not sure if we'll start using `github-merge.py` more or not; but I guess we should "fix" this anyhow in order to learn more how these work. It may be useful to move to merging commits locally and not relying on github being a good actor? 🤷

  ## What was done?

  ## How Has This Been Tested?
  Ran `github-merge.py` locally and it no longer complains about symlinks

  ## Breaking Changes
  None

  ## Checklist:
    _Go over all the following points, and put an `x` in all the boxes that apply._
  - [x] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

Top commit has no ACKs.

Tree-SHA512: be935bb9f5fa562fa7af5b33da239b6eca06bcf2790ee3f16d1b313b8b5ad1c878f4761b855cea5f7776f0241622f86feac91149a74c6d8940ddb8fb1b5700c4

src/immer/doc/guile.rst

@@ -1 +0,0 @@
-../extra/guile/README.rst

src/immer/doc/python.rst

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-../extra/python/README.rst