Itemize paper references again.

[jendrikseipp]

This requires a new txt2tags version, which we install via pip rather than bundling it.

[jendrikseipp]

I noticed that the autodoc tox step is not called for PRs. To enable it, I had to remove the build.py call from autodoc.py. But this actually brings the test more in line with the other tox tests, since they all assume that the planner is already built.

[FlorianPommerening]

I think not calling autodoc on each PR was by design: we certainly do not want to update the wiki before a PR is merged, and as a dry run, I don't really see the point because there is no way to see what the changes would look like in the wiki. It's also no "test" that can fail in a meaningful way, is it? I think running it on PRs is unnecessary work that just makes the actions take longer, but I don't feel too strongly about it.

The change to install txt2tags with pip rather than us providing a version in external, and the one about not building the planner anymore mean that is is more complicated now to call autodoc on the command line. Maybe not the most common use case, but I have done that in the past. For that, I think it would be useful to at least test the assumptions and print a useful error message. Something like "txt2tags not found, use 'pip install requirements.txt' to install it" (is that the right command?) for the dependency. For the build you could also add a message or just keep the build method and call it if the planner binary is not present. The new dependency should also be documented, probably here https://www.fast-downward.org/ForDevelopers/DevelopmentSetup

[jendrikseipp]

The autodoc tox test runs in a fraction of a second. And it failed in a meaningful way for me while working on this issue, so I think it's good to run the test.

If the binary is missing during an autodoc.py call, we automatically get "Could not find build 'release' at /home/jendrik/projects/Downward/downward/builds/release/bin. Please run './build.py release'." from the driver already. For the case where txt2tags is missing, I added an error message.

I wouldn't add the txt2tags dependency to the wiki dev instructions since tox installs it transparently.

Good to merge?

[FlorianPommerening]

Fine with me. I'd still add the dependency to the wiki because the tox installation doesn't help when using the script directly.