Option to report issue once per run as opposed to per page

[CharlesBelov]

If every page has the same issue with the same URL, please provide an option to only report that URL as a problem on the first occurrence.

For instance, if both page 1 and page 2 have a link to https://www.example.com/problempage3.htm, which returns 405 Method Not Allowed, only report https://www.example.com/problempage3.htm as an error on page 1. However, if https://www.example.com/problempage4.htm occurred on page 2 and not on page 1, https://www.example.com/problempage4.htm would be reported because it is not a duplicate.

This would help keep the report size smaller and avoid duplicate effort when plowing through the report, especially for links which are duplicated on every page of a large site.