setDisplayName
Renames @file to the specified display name.
The display name is converted from UTF-8 to the correct encoding for the target filesystem if possible and the @file is renamed to this.
If you want to implement a rename operation in the user interface the edit name (%G_FILE_ATTRIBUTE_STANDARD_EDIT_NAME) should be used as the initial value in the rename widget, and then the result after editing should be passed to g_file_set_display_name().
On success the resulting converted filename is returned.
If @cancellable is not null, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
Return
a #GFile specifying what @file was renamed to, or null if there was an error. Free the returned object with g_object_unref().
Parameters
a string
optional #GCancellable object, null to ignore