The splitting/deprecation of git checkout

The git checkout command has two distinct uses. One is to switch and/or create branches and the other is to restore files to a previous index. These two functions have been separated out to avoid confusion.

Switch

To switch branches, you should now use the following:

git switch <branch>

adding -c to create a new branch.

Restore

To restore files from a previous index, you should now use the following:

git restore -s <ref> <path>

This allows a new feature: restoring with patches using the -p command, similar to it's usage in git add.