chore: simplify code generation logic for a faster and better UX

[masih]

Related Issues

• Fixes Make make gen faster #8392

Proposed Changes

The changes here simplify the string of targets executed as part of make gen. The simplifications include:

• parallelised code generation whenever possible.
• re-implementation of documentation generation for a significant simplification and improved readability.
• unified mocks generation to avoid multiple slow calls to go run per package.

Note, the changes introduced here are purely mechanical and do not alter the Lotus node functionality.

Additional Info

Timing On CI

• Before: 2m 41s
• After: 1m 28s

Timing On my machine

• Before: make gen 105.22s user 56.84s system 152% cpu 1:46.46 total
• After: make gen 54.30s user 36.99s system 178% cpu 51.247 total

Checklist

Before you mark the PR ready for review, please make sure that:

• Commits have a clear commit message.
• PR title conforms with contribution conventions
• Update CHANGELOG.md or signal that this change does not need it per contribution conventions
• New features have usage guidelines and / or documentation updates in
  • Lotus Documentation
  • Discussion Tutorials
• Tests exist for new functionality or change in behavior
• CI is green

[github-actions]

Please update the PR title to match https://github.com/filecoin-project/lotus/blob/master/CONTRIBUTING.md#pr-title-conventions

PR title now matches the required format.

[rjan90]

I still have some cleanups/updates to do on my computer that makes it a little slow. But this is soooo much faster then when I ran a couple of days ago:

make gen 74.23s user 22.34s system 127% cpu 1:15.79 total

[masih]

There is room for more improvements, e.g. not generating files that need fiximports, etc. But the correct fix IMHO is to simply do a lot less, which is a large divergence from the current approach and a big diff to go with it.

For now, more CPU cores to the rescue.