Chalk extract doesn't differentiate between docker image and file

[eatonphil]

Description

If you have a path that happens to be in the same format as a Docker image chalk will select the file.

$ ~/chalk extract localhost:5000/wordsmith:latest
warn:  /home/admin/wordsmith/api/localhost:5000/wordsmith:latest: Artifact is unchalked
info:  /home/admin/.local/chalk/chalk.log: Open (sink conf='default_out')
info:  Full chalk report appended to: ~/.local/chalk/chalk.log
... omitted

admin@ubuntu:~/wordsmith/api$ ls
Dockerfile  localhost:5000  pom.xml  src
admin@ubuntu:~/wordsmith/api$ ls localhost\:5000/
wordsmith:latest

Perhaps better to have a flag that signals that this is a docker image? Or a docker:// prefix to show that you are intended this to be a docker image?

Impact

Dunno.