Update docs/development/getting-started.rst (the source for https://warehouse.readthedocs.io/development/getting-started/ ) to say, in the "Configure the development environment" section, something like:

"In case you are used to using a venv/virtualenv or virtual environment for Python development: For Warehouse development, don't use one. Our Makefile scripts and Docker container development flow create and remove virtualenvs as needed while you are building and testing your work locally."

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