ISL suggests `update --clean`, which doesn't exist

[arxanas]

Steps to reproduce:

1. Make some uncommited changes.
2. Try to Goto a different commit in the VS Code ISL.

Actual behavior:

See this message:

(commit, shelve, update --clean to discard all your changes, or update --merge to merge them)

But sl update --clean doesn't work; it looks like sl goto is the command instead. Perhaps update should be an alias for goto? (That's what Jujutsu does IIRC.)

Expected behavior:

All suggested options are valid sl commands.

[yancouto]

Yes, it's supposed to be goto instead of update. We will fix the documentation.