Special processing for loco control code characters

[LeftofZen]

See https://github.com/OpenLoco/OpenLoco/blob/f3ec658e4409b50259fb71fe0bb6936f3f23bc80/src/OpenLoco/src/Localisation/Formatting.h#L66 for the special control codes that can be specified in a string as per Locomotion's string definition. For example 123 is ASCII { but this doesn't represent the literal character, it represents a format specifier for the string, in this case an int32. In the UI w should simply display this to the user in a clear manner and perhaps display a table of valid control codes they can use.