document ruleset yaml

[pq]

The rulesets should have inline docs that explain (at least):

• what the rulesets are for
• how to use them, and
• include links to any supporting docs

[parlough]

Once descriptions are decided on I can I also include information in a follow-up to dart-lang/site-www#3064

[pq]

From @goderbauer in dart-archive/lints#4 (comment),

This file should probably contain a comment explaining that it should be used in addition to core.yaml - and not as a substitute.

(That was my first question I had first time looking at these files)

[pq]

RE: site updates, fyi @mit-mit who likely has ideas...

[parlough]

I have some initial thoughts here:
dart-lang/site-www#3228

[devoncarew]

I believe this was addressed by dart-archive/lints#88.