doc: enforce max-line-length lint rule

Includes 80 character limit for docs linter.

I managed to add the linter rule for the docs, but I'm not sure of an elegant way to fix existing lines than exceed 80 characters.

Fixes: https://github.com/nodejs/node/issues/18703

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)