There are a lot of warnings reported by markdownlint in the CI, this
commit aims at fixing all of them.

Tested :

No more warnings reported by markdownlint in the CI.

Change-Id: I92d24bc0efd230dd0974ff49853ef928caf1febd
Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>