Document automatic Wayland/Nvidia workaround in troubleshooting

[niksirbi]

References and relevant issues

Depends on napari/napari#9009
Related to napari/napari#8808

napari/napari#9009 makes napari automatically apply the Wayland/Nvidia startup workaround (setting QT_QPA_PLATFORM=xcb and PYOPENGL_PLATFORM=glx), and adds an in-app warning for the cases it can't cover. That warning links to the troubleshooting section updated here (#wayland-and-nvidia). See that PR
for the full background.

Description

This PR updates the "Running napari on Wayland with Nvidia cards" troubleshooting section to reflect the new automatic workaround in napari/napari#9009:

• Explains that recent napari versions set the required environment variables automatically at startup, so most users (launching via the napari command or a Python script) no longer need to do anything.
• Documents the manual workaround for the case the automatic fix can't cover: when a Qt application is created before import napari (e.g. in IPython or Jupyter when %gui qt runs first), the user must set the variables themselves before starting the session.
• Notes that user-set values are always respected.
• Adds a stable (wayland-and-nvidia)= anchor that the in-app warning links to, while keeping the original heading so existing links don't break.

[brisvag]

Love it!

[TimMonko]

Absolutely lovely! Thank you!!!! 🤩

I left two comments, but you are more then welcome to do with them as you please. :)

[niksirbi]

Thanks both! Probably it make sense to wait till we settle on how napari/napari#9009 lands before this one gets merged, right?

[TimMonko]

Thanks both! Probably it make sense to wait till we settle on how napari/napari#9009 lands before this one gets merged, right?

Yep! And because you have the "Depends on" in the OP our CI blocks it :)

[niksirbi]

Yep! And because you have the "Depends on" in the OP our CI blocks it :)

Good to know! I should start using that too.

[niksirbi]

I pushed an additional commit b8531b4 (this PR), as discussed in napari/napari#9009.

[TimMonko]

Looks great! Thank you for your continued effort and time on this!