Thank you for your post.
When editing a script, the auto-complete will select a value when you press return. If you press a space after "not", then "Notes::" will not be available. Likewise, if you press Escape, the auto-complete value will disappear. That is, you can type "not", press escape (to dismiss the auto-complete value of Notes::), and press return.
Please post your suggestion for creating a table/field with the same letters as an operator, and to not auto-complete for boolean operators, to our Product Ideas board at: Product Ideas
The Product Ideas board is monitored by Product Management and Development. All suggestions are discussed and considered for possible implementation in a future release.