EntityPrototypeFlag "get-by-unit-number" should not be mentioning input actions

[Quezler]

The flag suggests it can (in addition to making the entity support the get_by_unit_number) replace the cursor position with the unit number,
however after my initial attempts and a talk with boskid https://discord.com/channels/1214952937 ... 5478944928 it basically turns out that "trivia" is like completely useless to know, there's like no custom input event (with our without "include_prototype") capable that manages to get the unit number passed to the control stage, if anything it explains how a select few events are perceived in c++, this leads modders into a false sense of "oh hey i can use this for the control stage".

edit) continuance of the discussion with boskid: https://discord.com/channels/1214952937 ... 7740324965

[Bilka]

Thanks, done for 2.0.42.