Orphaned submodule gitlink breaks git submodule update --init --recursive

[Yui-Koi]

On init of submodules I hit,

fatal: No url found for submodule path 'experiments/exp8_reasoning_architecture/TinyRecursiveModels' in .gitmodules

The path is not listed in .gitmodules, but the gitlink still exists in the index and .git/config still holds:

$ git ls-tree HEAD -- experiments/exp8_reasoning_architecture/TinyRecursiveModels
160000 commit e7b68717f0a6c4cbb4ce6fbef787b14f42083bd9  experiments/exp8_reasoning_architecture/TinyRecursiveModels

Steps to reproduce

1. fresh clone
2. git submodule update --init --recursive

Proposed fix

• git rm --cached experiments/exp8_reasoning_architecture/TinyRecursiveModels
• rm -rf .git/modules/experiments/exp8_reasoning_architecture/TinyRecursiveModels
  And then commit the deletion.

Fyi, the work-tree directory is already absent.

Will open a quick PR unless this folder was intended to be a submodule if so please provide the upstream URL (or feel free to push the fix yourself).