Assert: Minor cleanup for QUnit.assert documentation

[JamesMGreene]

Some minor cleanup of the wording for QUnit.assert.

[jzaefferer]

That still sounds wrong. Aren't we passing an instance?

[JamesMGreene]

Aren't we passing an instance?

That's not 100% accurate either. It is an instance but not an instance of QUnit.assert: QUnit.assert is the prototype of the constructor that gets instantiated. I doubt we want to go into that much detail in the documentation, so we can just pick a phrase that is mostly correct but much shorter: either "copy of" or "instance of" would be fine by me but the current text is definitely not right.

[jzaefferer]

I prefer "instance of" over "copy of". We could also add another paragraph that has a more accurate description for anyone interested.

[JamesMGreene]

Updated with "instance of". Chose not to add another paragraph qualifying that further... they can look at the code if they want to know the nitty gritty details like that, I figure.

I also dropped the reference to QUnit.asyncTest as that is now deprecated.

[leobalter]

👍 (LGTM)

[jzaefferer]

Why is "callbacks" in plural?

[jzaefferer]

Turned that "callbacks" into singular "callback", squashed and merged.