Add --irreversible-delete to git diff in patch-commit

[webstrand]

• I'd be willing to implement this feature (contributing guide)

Describe the user story

When deleting files from a package under pnpm patch it is not desirable to retain the full contents of the deleted file in the resulting patch file created by pnpm patch-commit it wastes repository space and can be confusing when fixing up a patch that failed to apply.

Describe the solution you'd like

Add --irreversible-delete to /packages/plugin-commands-patching/src/patchCommit.ts:64 so that the patches do no retain the full contents of the deleted file.

Describe the drawbacks of your solution

As far as I know, there are no drawbacks. The contents of any deleted file are retained by the package repository.

Describe alternatives you've considered

Manually editing the resulting patch files is finicky and it's easy to break the patches.

[zkochan]

Sounds good to me, I wonder why Yarn is not doing the same

cc @arcanis

[arcanis]

Sounds good to me, I wonder why Yarn is not doing the same

Seems a good idea - we just didn't realize the rm operation was including the old content, which isn't super useful indeed 🤔