Add example for compile current env packages

[T-256]

Summary

I was going to create a feature-request issue for adding graph like showing of currently installed dependencies in venv, but then I found uv pip freeze | uv pip compile is what I'm looking for.

As one who manually pip-installs packages every once in a while (instead of edit requirements.in each time), after a while I would need to have graph of installed packages (e.g. to see how uninstallinga packages effects on others).

I found this command is so useful and wondered if we could have this in docs as one of uv features.

Test Plan

[charliermarsh]

Can you say a bit more about how / when you use this?

[T-256]

Can you say a bit more about how / when you use this?

When I need a dependencies-tree in an environment, and I didn't have/use requirements.in.
So, first step is to export deps using pip freeze. Also, I don't want to create temporary requirements.in, so I pipe it to pip compile.

[zanieb]

Thanks!