Loosen extension requirements for executable-like files

[Voltra]

Is your feature request related to a problem? Please describe.
Let's say we're on windows, in any terminal we can use npm to run it, not npm.CMD, just plain npm. In NuShell, which npm will find the correct file, however running npm will result in an error : file not found. (os error 2). Using npm.cmd will run the program just fine.

Describe the solution you'd like
I'd like to be able to run programs (such as npm) that are available in PATH that have fairly executable-like extensions (e.g. .cmd on windows).

Describe alternatives you've considered
I can't think of any alternative solution.

Additional context
This is a problem encountered mostly with installed binaries (or executable scripts) from any package manager.
Note that on Windows the PATHEXT environment variable lists the extensive list of file extensions in search order.

[steveklabnik]

Ran into this with Visual Studio: Code today. 👍

[jntrnr]

This should be better now. If you still find cases that don't work with the latest master please re-open