optional install the crossplane cli is out of date

### URL

since we switched the cli to its own repo this guide is not up 2 date anymore:

https://docs.crossplane.io/v2.4/guides/install-from-source/#optional-install-the-crossplane-cli

### What's Wrong?

Start with the linked install-from-source guide at the optional Crossplane CLI section. Check the current CLI repository and compare its installation instructions with the page. Update that section to reflect the CLI's separate repository, then verify the rendered documentation is accurate.

Written by the indexing model from the issue text.