file for a given display.name (i.e. a UTF8
version of the name). If this function fails, it returns NULL and error will be
set. This is very useful when constructing a GFile for a new file
and the user entered the filename in the user interface, for instance
when you select a directory and type a filename in the file selector.gFileGetChildForDisplayName(object, display.name, .errwarn = TRUE)GFile.