osc fork doesn't support "project/package" syntax

[cboltz]

osc fork doesn't support the project/package syntax that is supported by lots of osc commands. Instead, I'm forced to use project package.

This is annoying because I manually have to replace the / after copying from an OBS URL. It is also inconsistent with lots of other osc commands (co, branch etc.)

Versions

• openSUSE Tumbleweed 20260514
• osc-1.26.0-1.1.noarch

To Reproduce
Steps to reproduce the behavior:

1. Run command osc fork graphics/libwebp
2. See error (pasted below)

Expected behavior
osc fork should replace the / with a space to separate project and package name (like many other osc commands already do)

Screenshots, console outputs

# osc fork graphics/libwebp
usage: osc [global opts] fork [-h] [-q] [...]
osc [global opts] fork: error: Invalid project: graphics/libwebp
# osc fork graphics libwebp
Forking git repo jengelh/libwebp ...
[...works...]