* retroarch: add page * Update retroarch.md * Update pages/linux/retroarch.md Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * Update pages/linux/retroarch.md Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * Update pages/linux/retroarch.md Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * Update pages/linux/retroarch.md Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * Update pages/linux/retroarch.md Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com> * Update retroarch.md Co-authored-by: Emily Grace Seville <emilyseville7cf@gmail.com>