Support building mdoc through Mill on dev

[michael-etzkorn]

Type of issue: feature request

Impact: no functional change

Development Phase: request

Other information

What is the current behavior?
Since merging 0b7fef4, the steps to build mdoc are no longer supported and need a Mill build equivalent to check the mdoc against the latest dev branch.

[FurryAcetylCoA]

We can use yoohaemin/mill-mdoc to generate mdoc with mill. Note: the readme.md in this fork is not up to date. com.yoohaemin::mill-mdoc::0.0.3-7-355e3e-SNAPSHOT is the first release compatible with mill 0.11.

However, I'm not sure were to mix the MDocModule trait in. I tried to mix it with RocketChip and while it did compile the docs but it failed at emitting SystemVerilog(adder_tutorial.md:315). This issue arises because chisel5 compilation requires the plugin, and 'm not familiar with build.sc structure used by rocketchip. I don't know how to fix it ( should I just use another object extended from RocketChip ? )

Also, there are problems with executing ChiselStage.elaborate(top.module) in select_tutorial.md:80 even after adjusting the package path. I believe it has something to do with the internal API change of chisel, which, unfortunately, I'm also not familiar with.