Documentation: More markdown fixes after switching to sphinx

Fix markdown code to work with sphinx.

Change-Id: I52014494dc2d09731fe14ab527073352ada860d1
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/26544
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
3 files changed