NB flagged as incorrect

**What got flagged?**
The abbrieveated form of the Latin expression nota bene, NB. It practically means "note well", and it is still used in English.
**Why is this incorrect?**
It is a legitimatly used expression in English

**Example of correct usage:**
NB! Do test your translations! If you mess up placeholders (omit one, add one too many or use wrong type), then the user will see a crash, not just a broken translation!

The issue names no files or tests. Start by reproducing the warning with the provided “NB” example and trace which grammar-checker rule reports it; done means the checker accepts this legitimate abbreviation without regressing other translation-placeholder warnings.

Written by the indexing model from the issue text.