MDX: raw URLs triggering on vocab in 3.10

[rainecheck]

Check for existing issues

• [x] Completed

Environment

Docker image for 3.10

Describe the bug / provide steps to reproduce it

In the new MDX support, raw urls (e.g. The link is http://github.com rather than The link is [http://github.com](http://github.com)) are setting off content in accept/reject.txt: 149:11 error Use 'GitHub' instead of 'github'. Vale.Terms

[jdkato]

See https://github.com/errata-ai/vale/issues/320.