Omit a warning when attempting to use cucumber-expressions in regular expressions

[badeball]

Example of this:

Given(/^foo {string}/, () => {});

This is unequivocally an error and we can give a more appropriate message than that "a step definition is missing". Furthermore, users that really need this can supress the error like

Given(/^foo {string}/, { supressCucumberExpressionWarning: true }, () => {});

[badeball]

This happens all the time, most recently here.