assert: clarify Eventually documentation

[st3penta]

Summary

The documentation of the Eventually function is a bit ambiguous, not specifying what happens when the execution of the condition function takes longer than one tick.

Changes

Clarify the Eventually function description by describing the behavior of the condition function execution in the above scenario.

Related issues

Closes #1443

[arjunmahishi]

I feel like this comment is answering a very specific question about the implementation. If the user is not concerned with this detail, it might confuse them.

IMO, we can leave the doc comment as it was before and add comments within the function that describe the implementation details.

---

Perhaps here we can describe that "the ticker is paused while the condition function is being evaluated. If the condition function yields false it is resumed again"

testify/assert/assertions.go

Lines 1880 to 1888 in 890a441

	case <-tick:
	tick = nil
	go func() { ch <- condition() }()
	case v := <-ch:
	if v {
	return true
	}
	tick = ticker.C
	}

[st3penta]

Actually i found that there are 3 occurrences of this same ticker logic: here, here, and here. Should we replicate the same comment in all those 3 points?

I liked the idea of moving the explanation closer to the implementation, but actually the code itself is pretty simple, so maybe the comment isn't really necessary, what do you think?

[arjunmahishi]

but actually the code itself is pretty simple

Agreed. We can skip it then.