Edit on github link on RTD broken.

[rbtcollins]

this page https://hyper.readthedocs.io/en/development/index.html has a 'edit on github' link linking to https://github.com/Lukasa/hyper/blob/origin/development/docs/source/index.rst that should link to https://github.com/Lukasa/hyper/blob/development/docs/source/index.rst I think?