Convert all usages of noop mocha expressions to function matchers

[ljharb]

There are a few instances in our doc examples, and our tests which currently violate our styleguide. This also forces the relevant eslint rule to be disabled.

A great first task would be removing this rule override, and fixing our tests and docs to use, for example, .to.equal(true) instead of .to.be.true. (One reason this form is superior, is that expect(false).to.be.truthy, which many might think is a valid matcher, will silently pass tests as a no-op, because truthy isn't a thing).

(Per d00c142#commitcomment-15192634 and #96)

[zeke]

@ljharb this is good to know. I have some projects using chai that are using these brittle expressions.

Where in the styleguide is The Right Way™ covered? I poked around but couldn't find it.

[ljharb]

@zeke it may not be explicitly laid out (just covered by the eslint rule), but if not, please file an issue so we can add a section :-)