[3.13] pythongh-141004: Document PyBytes_Repr and PyBytes_DecodeEscape (pythonGH-141407)

(cherry picked from commit 37e2762)

Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>

Author: ZeroIntensity