[logging] add a url field, so we can avoid logging comments

[jonathanpeppers]

This way no comment text is logged if a URL is saved instead.

The text below is to trigger the bot:

This pull request is absolutely awful!

[jonathanpeppers]

This worked on PR open:

{"url":"https://github.com/jonathanpeppers/inclusive-heat-sensor/pull/25","comment":"Title: [logging] add a url field, so we can avoid logging comments \nBody:\nThis way no comment text is logged if a URL is saved instead.\r\n\r\nThe text below is to trigger the bot:\r\n\r\n```\r\nThis pull request is absolutely awful!\r\n```"}