Issue Summary

This is reproducible on Data Center: yes

If a URL is entered in a comment that contains a at symbol, it gets stripped out when the comment is rendered, changing a URL like https://www.npmjs.com/package/@babel/preset-env into https://www.npmjs.com/package//preset-env

Steps to Reproduce

1. Enter a URL as a comment with a at symbol, e.g. https://www.npmjs.com/package/@babel/preset-env 
2. Save/publish comment

Expected Results

URL text should display as entered

Actual Results

https://www.npmjs.com/package/@babel/preset-env is displayed as https://www.npmjs.com/package//preset-env

Workaround

None. Link still works.