Documentation Update

[delaschwein]

Description

As always, you can see the updated docs here: https://minigrid.fenggu.me/

Fixes # (issue) Removed the scripts for generating api/wrappers, env/index, env/design, and index page. Use autodoc to group wrappers Renamed reinforcement learning to training an agent

Type of change

Please delete options that are not relevant.

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Screenshots

Please attach before and after screenshots of the change if applicable.

Checklist:

• [x] I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes

[mgoulao]

Remove the .placeholder files where they are not needed