-h help flag collides with user defined -h

[nickgarvey]

Configuration:
User defines their own flag that uses -h

Expected behavior:
Running tool --help doesn't include -h as short hand for --help

Actual behavior:
-h is included for both --help and the custom flag

e.g.

ngarvey@challenger:~/projects/screeps-docker$ docker run tester cli --help

  Usage: cli [options]

  Connect to the CLI interface of the main process.

  Options:

    -h, --help         output usage information
    -p, --port <port>  Default is 21026
    -h, --host <host>  Default is localhost

[shadowspawn]

The masked help options are no longer displayed from Commander v5.1.

https://github.com/tj/commander.js/releases/tag/v5.1.0

Thank you for your contributions.