Implement "Did you mean?"

[felixSchl]

Should be fairly straight forward. We already have e.g. Unknown option --hel. Expected --help, so make this look like: Unkown option --hel. Did you mean --help? based on a substring match or diffing.

[matthewmueller]

i just implemented something like this. here's a quick link dump of two different options:

• https://github.com/mattyork/fuzzy
• https://github.com/wooorm/dice-coefficient