Problem
In Abusefilter, when writing code, it is difficult to add variables/functions when we know which one we want to use but don't remember its exact syntax: it requests a) to use the dropdown list, which is very long and not convenient, or b) to search it somewhere else in the same filter or in another filter, or c) to search for its syntax in the mediawiki documentation.

Proposed solution
Add autocomplete/word completion feature for available variables and functions in the edit box.