Add details about real-time on interim releases of Ubuntu (#62)

[khbecker]

No description provided.

[khbecker]

@AnneCYH Do you know why the main documentation check is failing? I can access the URL it says it can't access. Should I keep retrying until it works?

Edit: It took 3 tries, but it worked! ¯_(ツ)_/¯

[khbecker]

Given the changes coming to the realtime kernel on Ubuntu Core, I'm removing the mention of the 6.11 kernel on Ubuntu Core for now. We can add that info later once we've decided on the plan.

[khbecker]

The ubuntu-realtime package for oracular is queued for release. Once released, I'll mark this PR ready for review.

[AnneCYH]

@AnneCYH Do you know why the main documentation check is failing? I can access the URL it says it can't access. Should I keep retrying until it works?

Edit: It took 3 tries, but it worked! ¯_(ツ)_/¯

Hey @khbecker , the URL checks are a little unstable but we haven't found out why exactly this is. We introduced a PR recently in the documentation starter pack template to increase the retries to 3 times (seems to be same as your magic number!).

I'll add the same to our repo.

[farshidtz]

Looks good. Thanks.
I have a suggestion about the examples in the title.

[farshidtz]

Is it necessary to give examples? Maybe this could link to releases.rst and skip the examples. They are oversized:

Maybe move them below?

[farshidtz]

I'm not sure adding headers to a re-usable text is the best idea because it makes assumptions about the caller's hierarchical structure. What do you think @AnneCYH?

Currently, it turns out okay:

• https://canonical-ubuntu-documentation-library--85.com.readthedocs.build/real-time/en/85/how-to/enable-real-time-ubuntu/
• https://canonical-ubuntu-documentation-library--85.com.readthedocs.build/real-time/en/85/tutorial/2-install-rtu/

[khbecker]

That makes sense. I think it works in this case, but I can see how it could become a problem. @AnneCYH, I'm fine with whatever the best practices are here.

[AnneCYH]

If the intent is to keep the headings consistent, then I would use different markers to include the header for different levels. But it'll be a lot cleaner with Markdown compared to rST just because of the syntax.

For example, in the reuse file:

start-level-2
## Level 2 heading starts here
end-level-2

start-level-3
### Level 2 heading starts here
end-level-3

And in the source file referencing it, for a level 2 heading:

```{include} /reuse/myst-install.txt
:start-after: start-level-2
:end-before: end-level-2
```

I know it's not exactly a reuse but it keeps everything in one place for easy maintenance.
Otherwise it would be better to just exclude it from the reuse file.

In this case I would leave the headings in the reuse file since (as you both mentioned) it works for now. But I would leave a note to indicate that the heading levels need to be taken into account when reusing this file.

So for example in install-rtu.txt, i would a line to this effect:

.. NOTE: heading levels must be taken into account when including this file

LTS releases of Ubuntu (e.g. 22.04, 24.04)
------------------------------------------
[...]

[AnneCYH]

1. I agree about removing the releases from the headings.
2. I would like to the releases.rst file as suggested by @farshidtz and also link to https://ubuntu.com/about/release-cycle for "more information" for users who may not be aware what an LTS vs interim release is.