Add a default alias for the Dockerfile filetype, which is capitalised for some users.
Add a default alias for the Dockerfile filetype, which is capitalised for some users.

breed808/ale,hernot/ale,breed808/ale,IngoHeimbach/ale,w0rp/ale,IngoHeimbach/ale,esran/ale,neersighted/ale,w0rp/ale,adriaanzon/ale,neersighted/ale,doits/ale,IngoHeimbach/ale,hernot/ale,neersighted/ale,w0rp/ale,breed808/ale,hernot/ale