Use `classes` matcher pattern option

@mansspams
Can you provide screenshot of error of browser console?

I'm seeing the same issue. Here's a screenshot of the console — you can see a warning for each link style class I've defined:

Here are the link styles I'm using for testing:

a.btn|Button
a.btn.btn--primary|Button: Primary
a.btn.btn--secondary|Button: Secondary
a.btn.btn--large|Button size: Large
a.btn.btn--block|Buttons size: Wide

Steps to reproduce:

1. Visit your text format and add the link styles above (or any other, really)
2. Open your browser's console
3. Create a new node for any entity that uses the text format configured above
4. Create a link and apply one or more link styles
5. Save the node (no warnings appear at this point)
6. Edit the node again
7. You should see one warning for each configured style in the console

There is a patch on 🐛 Existing classes are not used as default values Needs review that should resolve this issue.

Sounds like we can close this as a duplicate then? Feel free to reopen if otherwise.