When a user adds new terms to any blacklist, we should provide the user the option to delete all posts matching that criteria.
For example:
1. User adds "cat OR dog" to blacklist
2. User hits save to save the search with new settings
3. System prompts "would you like to delete results already in your data set that match these terms? This will remove [count of matching terms] mentions from the search.
4. User clicks yes, it deletes the mentions, user clicks no, it keeps them in
Guest
