extract reference documentation on remote builds

[fricklerhandwerk]

Motivation

#9202 (comment)

Context

This is a large diff, but in essence it does this:

• move all reference documentation to the builders configuration setting
• reword documentation on machine specification, add examples
• disable showing the default value, as it rendered as @/dummy/machines, which is wrong
• highlight the examples
• link to the configuration docs for distributed builds

This work is sponsored by Antithesis ✨

Priorities

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[Janik-Haag]

Is there a way of rendering these changes locally, reading the diff github produces is a bit hard, I would gladly help reviewing this.

[fricklerhandwerk]

No, unfortunately still, you have to go through the whole build process locally to produce a rendering. Run make manual-html when following build instructions. It requires building all of Nix, so it will take a while.

[fricklerhandwerk]

The speed factor changed from int to float in #9841, and this is not accounted for here because I'm not sure this is a good idea #9841 (comment). I suggest merging as is and resolving that before the next release.