Registers a hook function for a specific operation.
- "string" - The operation for which the hook function should be called. Currently supported hooks: "setTextPosition" (the hook is called everytime the position of a displayed text is set), "getActionText" (the hook is called everytime to get the currently displayed action text).
- "string" - The name of the lua function which is called when the hook is executed. "setTextPosition": The function should take exactly one argument which is the affected visionaire object. The function must return a boolean value: true if the operation was handled in the hook function, false if the operation was not handled and should be handled by the engine (as if there were no hook).
- "getActionText": The function should take exactly one argument which is the current mouse position (a table containing x- and y-position). The function must return a string value which will be used as the current action text.