Update python publisher tutorial with links to relevant docs

[EmmanuelMess]

Description

Update python publisher and subscriber tutorial with links to relevant documentation.

Addresses #4985

Did you use Generative AI?

No.

Additional Information

This first PR is to test the idea. Also see that rosdep's link is explicitly set because the macro doesn't work, see #6180.

[fujitatomoya]

lgtm with green CI.

[fujitatomoya]

@christophebedard can i have a second review on this?

[christophebedard]

This first PR is to test the idea.

This PR is OK, but, similar to what was mentioned in #4985 (comment), I would not systematically do this for other articles.

Instead of writing

`Node <{package_link(rclpy)}api/node.html>`__ class

everywhere to link to the API docs for Node, we need tooling that lets us write something like

{api(rclpy, rclpy.Node)} class

and expands it to the correct page. For now, I think we're still generally working on making sure API docs are properly generated, which does mean changes to rosdoc2, but it mostly means fixing a lot of the packages (e.g., ros2/geometry2#857). Then we can think about how to create/find tooling to easily link to it from here. Otherwise the page we link to may not exist or the actual URL may change shortly after.

[Shivam-Bhardwaj]

I can look up for developing/incorporating a proper system for links in a seperate issue. Or help with something that's WIP.

Can this be taken care on the URL side? Maintaining a database of URL matched with the doc links?

[christophebedard]

Last minor comment

[christophebedard]

I can look up for developing/incorporating a proper system for links in a seperate issue. Or help with something that's WIP.

Can this be taken care on the URL side? Maintaining a database of URL matched with the doc links?

I would hold off for now. Please see #6186 (comment)