tweak build dependency hint wording

[KTibow]

Summary

old hint wording is like

hint: This error likely indicates that `[email protected]` depends on `pybind11`, but doesn't declare it as a build
dependency. If `pufferlib` is a first-party package, consider adding `pybind11` to its `build-system.requires`.
Otherwise, either add it to your `pyproject.toml` under:

[tool.uv.extra-build-dependencies]
pufferlib = ["pybind11"]

or `uv pip install pybind11` into the environment and re-run with `--no-build-isolation`.

which, in the case where it's a first-party package, is a little vague and deemphasized.

this pr uses wording that treats both cases as equals:

hint: This error likely indicates that `[email protected]` depends on `pybind11`, but doesn't declare it as a build
dependency. You likely should tweak your `pyproject.toml`:
# if pufferlib is first-party
[build-system]
requires = ["pybind11"]
# otherwise
[tool.uv.extra-build-dependencies]
pufferlib = ["pybind11"]

or `uv pip install pybind11` into the environment and re-run with `--no-build-isolation`.

[zanieb]

I think we need to consider how we want to do multiline code formatting in hints like this. I believe that's why we have different instructions for the first-party case (it's also less common, and I think it's probably fair to de-emphasize?)

[KTibow]

If this change doesn't make sense, an alternative is to automatically detect whether the package seems first-party (not necessarily with rigor). Then this deemphasis would be very logical.

[zanieb]

First-party in this case could just be that you own the package. There's no way easy to detect that.