New check to enforce line length?

I would like to be able to lint my RST files for excessively long lines. Since this is likely to be controversial, the new check might best be ignored by default?

i.e. something similar to the flake8 code E501 for maximum line length, which can be configured at the command line:

  --max-line-length=n   Maximum allowed line length for the entirety of this
                        run. (Default: 79)

I would suggest using the same default line length (and double checking if this counts the new line character or not).