Add section on disabling scaladoc

[majk-p]

Disabling scaladoc is known to improve build times for large codebases (example: scala/scala3#18157). Multiple projects do it (example https://github.com/scala/scala/blob/2.13.x/build.sbt#L362) but it doesn't seem to be documented. Hopefully that's useful.

Also please let me know if there are other/better options to do it.

[majk-p]

Doing some more search over Github repositories, I noticed combined use of Compile / doc / skip := true along with emptying Compile / doc / sources. Should both be referenced in the docs?

[eed3si9n]

I don't know if Compile / doc / skip does anything, so I'd recommend against that unless it's proven to be useful.

[eed3si9n]

Disabling scaladoc is known to improve build times for large codebases

What does "build times" mean here? I don't think compile or test would invoke doc. Do you mean for publishLocal?

[majk-p]

Do you mean for publishLocal?

Yes, in my quite specific case I need to run publishLocal against some of my generated sources to run scripted tests. Do you think it's better to reword it to something like reduce the time consumed by publishing task?

[majk-p]

CLA signed