`Functor OptDescr` is incorrectly marked as @since 4.6.0.0

Summary

Location of documentation issue: the Haddocks of base, specifically System.Console.GetOpt.

The instances for Functor OptDescr, Functor ArgDescr and Functor ArgOrder exist since base-4.7.0.0, but are annotated to exist since base-4.6.0.0, which is wrong.

Source: Compare src of 4.6.0.0 with 4.7.0.0. The incorrect 4.6.0.0-annotations can be seen here.

Proposed improvements or changes

Just correct the three annotations.