Followup to #1254 Instructions for mimicking GFM
Update github-pages.md

removed settings that don't influence the rendering
Updating to 848a11b3a8275ae932d45c8e98a5aefb7c2fd3f7.
Revert "Updating to 848a11b3a8275ae932d45c8e98a5aefb7c2fd3f7."

This reverts commit 88b3081bdbca57fd883306e4a6b8b19a6c2c6dc1.
Merge pull request #1614 from robkorv/gfm-additions

Followup to #1254 Instructions for mimicking GFM