html pattern attribute does not appear in red in NotePad++

I just want to understand why it doesn't, since all of the other attributes in my code are "red". (although the "pattern" attribute does work when launched)

Password:
<input type="password" name="password" pattern="(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}" title="Enter a password that is minimum 8 characters, 1 lowercase characher and 1 uppercase character."><br />