Force canonical URLs to include ROS distro

[attu0]

Description

This PR fixes canonical URL generation for sphinx-multiversion builds by
explicitly setting html_baseurl to include the ROS distribution
(e.g. https://docs.ros.org/en/rolling).

This prevents mirrors or alternate build environments from generating
incorrect canonical URLs that omit the ROS distribution or use
non-official domains.

Fixes #6112.

Did you use Generative AI?

Yes — ChatGPT (for guidance and explanation only).

Additional Information

• Implemented as a clean commit on top of rolling
• No unrelated documentation history included

[attu0]

@fujitatomoya Thanks for the guidance!

I’ve recreated the change as a clean commit on top of rolling and opened
a new PR targeting the rolling branch, as requested.

[tfoote]

This doesn't appear to fix the problem. Running make html with this patch The canonical urls aren't changed.

This is inside the sphinx multi version logic which is only going to trigger if you use sphinx multi version not the basic keys. RUnning this version the canonical urls arn't changed for make html.