feat: Remove LintRule::docs()

[bartlomieju]

This commit removes LintRule::docs() method and consequently all .md files
with documentation for the lint rules.

These docs now live at https://github.com/denoland/docs/tree/main/lint/rules.

Some code from dlint binary that prints these docs have been removed too
and instead points to relevant https://docs.deno.com/lint/rules/ pages.

This will allow to save about ~400Kb from the deno binary size.

[dsherret]

Nice!