Before we used to evaluate all named arguments as local paths
first. This means that the following could be a name conflict.
$ brew edit src
If there was a local file or directory named src, it would default
to that. Otherwise it would search for a formula/cask with the
same name and return that.
Now it will only default to the local path if the named argument
starts or ends with a slash ('/') or includes a period ('.').
This means that in the event of a name clash with a normal package
name it will default to the package instead of the local file.
It also fixes an edge case where the following would be interpreted
as a tap name.
$ brew edit /src
23b277bbd7