removed the validate-links command line flag and related functionality

[devoncarew]

• removed the validate-links command line flag and related functionality

This feature was enabled by default when running dartdoc via bin/dartdoc.dart. From testing, when generating docs for package:win32, 90% of the generation time was spent parsing and validating html which we ourselves had just generated. I don't think this feature is worth the cost.

dart doc does expose the --validate-links flag (validation is off by default). When dartdoc next rolls into the sdk we'll need to update the dart tools, changelog, etc.

[devoncarew]

It looks like the flutter bot is failing due to the fact that we no longer support a no-validate-links cli flag. I think we should just remove the use of the flag on the next roll. (For the dart doc command, we'd likely want to keep the flag, turn it into a no-op, and warn people when it is used)

[srawlins]

I think we need flutter buy-in that they are ok with removing this functionality.

I also think the functionality is useful when making changes to dartdoc. So it is good to use in our tests and development workflows, but I don't think it is very useful for end users. The only cost is time, so maybe flutter and pub think the verification is worth it. 🤷

[devoncarew]

Ah, I assume from the error that flutter is sending in the --no-validate-links flag? I'll find the reference.

[srawlins]

Oh, lol, I didn't read that closely enough. That's a big win then!