Docs: dulwich.porcelain.checkout_branch is not documented

[domWalters]

From: https://www.dulwich.io/apidocs/dulwich.porcelain.html

A checkout function is mentioned but not documented.

The porcelain module appears to provide checkout_branch which works, but isn't in the API listing.

[domWalters]

Actually, it looks like all commands that have been added over the last two years are not on the docs site:

• checkout_branch
• cone mode{_init, _set, _add}
• for-each-ref
• sparse_checkout

[domWalters]

Docs site appears to use v0.20.50:

• https://www.dulwich.io/docs/api/dulwich.porcelain.html#module-dulwich.porcelain:~:text=dulwich%200.20.50%20documentation
  • Version is at the top of this page
• https://github.com/jelmer/dulwich/releases/tag/dulwich-0.20.50
  • This is the tag that its from

This is from October 2022.

I did a local build from the git clone and it correctly made the 0.22.9 docs locally.