Typo in metadata docs page

Hello! I hate to be that person who opens tiny PRs for typos in docs (and I couldn't here because the repo has probably sensibly stopped people opening endless PRs!) - but there is a typo on the docs metadata page.

I humbly supply this patch in case there is some kind of automated process that might be able to apply it and get it fixed - if not feel free to close this!

0001-docs-fix-typos-in-metadata-docs.patch