pip cache remove for out-of-test testing of builder plugins.

docs/how-to/plugins/testing-builds.md

@@ -75,5 +75,7 @@ version = "0.1.0"
     ...
 ```
 
+Alternatively, you may wish to perform `pip cache remove hatch-plugin-name` before testing it manually on some project with `hatch build --target hatch-plugin-target`. This is suitable when developing a plugin in tandem with another project consuming it. However, it is not advisable for writing tests inside a builder plugin project, self-contained, as it modifying the global cache of the system rather than working around it at the test level. For writing tests, the former method is advisable.
+
 !!! note
     This example chooses to ignore copying `.git` for performance reasons. You may want to ignore more patterns, or copy only specific paths like [this plugin](https://github.com/hynek/hatch-fancy-pypi-readme/blob/main/tests/conftest.py) does.