Revert "Add .md and .markdown to use MdRenderer"
Revert "Add .md and .markdown to use MdRenderer"

This reverts commit 14b47195735461dc2a61541dfc48d5377a0f1bb1.

TomBaxter/modular-file-renderer,rdhyee/modular-file-renderer,Johnetordoff/modular-file-renderer,Johnetordoff/modular-file-renderer,CenterForOpenScience/modular-file-renderer,rdhyee/modular-file-renderer,Johnetordoff/modular-file-renderer,TomBaxter/modular-file-renderer,felliott/modular-file-renderer,rdhyee/modular-file-renderer,felliott/modular-file-renderer,TomBaxter/modular-file-renderer,CenterForOpenScience/modular-file-renderer,CenterForOpenScience/modular-file-renderer,AddisonSchiller/modular-file-renderer,TomBaxter/modular-file-renderer,CenterForOpenScience/modular-file-renderer,Johnetordoff/modular-file-renderer,felliott/modular-file-renderer,felliott/modular-file-renderer,AddisonSchiller/modular-file-renderer,AddisonSchiller/modular-file-renderer,rdhyee/modular-file-renderer,AddisonSchiller/modular-file-renderer