I am using the Quartus II text editor. Please tell me how to stop the function that predicts display by input characters

This feature is set to predict and display Autocomplete text.

There are multiple levels of settings for the predictive display feature, and you can even turn it off completely.

How to change settings
・ Select Tools ⇒ Options
・ Select Text Editor ⇒ Autocomplete Text from Category
・ Uncheck the Autocomplete text check Box to turn it off completely.
Alternatively, it is possible to use some prediction functions by changing the display level item.