Update getting_started.rst to add uv

[godalming123]

Reduces the necessity for #18971 or #17214 by explaining how to use mypy with uv.

[sterliakov]

I'm afraid this is a bit unfair. There is poetry, there is pdm, there is pipx - are we going to enumerate all package managers here? pip is the "default" one, so mentioning pip is reasonable. Everything else is user's homework IMO: "how to run a tool using your package manager?" I'm not a maintainer here, so please don't treat the comment above as a binding disapproval, let's wait for someone from the core team to comment.

[sterliakov]

This sentence also implicitly says "we do support pip and uv, but may not support other package managers", which is a false impression - mypy does not care which installation method was used, apt-get install mypy works on Ubuntu as well (even though it installs an ancient version). Perhaps

Suggested change

	Mypy requires Python 3.9 or later to run, and can be installed through either pip or uv.
	Mypy requires Python 3.9 or later to run, and can be installed via pip, uv or another package manager.

Here's how ruff explains its installation (note that they have to mention uv as that's another tool from Astral.sh, good for marketing, "recommended" is there for the same reason): https://docs.astral.sh/ruff/installation/

[hauntsaninja]

Thanks, but I don't think we need to do this. We expect our users to know how the packaging tools they're choosing work. The information we'd like to convey here is a) the project name on PyPI is mypy, b) what the mypy part of the command you'd use to run mypy looks like.