toFormats
Creates a new GdkContentFormats
from the given @builder.
The given GdkContentFormatsBuilder
is reset once this function returns; you cannot call this function multiple times on the same @builder instance.
This function is intended primarily for bindings. C code should use method@Gdk.ContentFormatsBuilder.free_to_formats.
Return
the newly created GdkContentFormats
with all the formats added to @builder