Type alias OperatorKey

OperatorKey: "in" | "notin" | "isnotnull" | "isnull" | "checked" | "unchecked" | "contain" | "start" | "end" | "=" | "<" | "<=" | ">" | ">=" | "<>"

Represents possible keys for the comparative operators.

These keys are used to identify and select the comparative operators in the filter.
Each key corresponds to a specific operator, such as in, notin, isnull, etc.
They are used throughout the filter control to manage the state of the selected operator and to perform the corresponding comparison when filtering data.