Update installation-docker.rst
Update installation-docker.rst

Changing feature to featured and changing "based in a linux kernel" to "based on a linux kernel"
mozilla/mozillians,johngian/mozillians,fxa90id/mozillians,akatsoulas/mozillians,mozilla/mozillians,akatsoulas/mozillians,johngian/mozillians,johngian/mozillians,johngian/mozillians,akatsoulas/mozillians,fxa90id/mozillians,fxa90id/mozillians,mozilla/mozillians,fxa90id/mozillians,mozilla/mozillians,akatsoulas/mozillians