Clarify effect of .skip() (#3947)
Clarify effect of .skip() (#3947)

The fact that code inside of a skipped suite is executed, is potentially
counter-intuitive.  By using alternative phrasing, we make it clear how
mocha handles code in skipped suites.

Closes #3932
mochajs/mocha,outsideris/mocha,adamgruber/mocha,adamgruber/mocha,mochajs/mocha,outsideris/mocha,adamgruber/mocha,mochajs/mocha