Fix return type of findDeep, Add missing field to IDeepEntry

[casamia918]

I fixed return type of findDeep and add context field to IDeepEntry interface.

But, for now, the type of parent field of IDeepEntry is not IDeepEntry. It is just same with parent.value.
It should be fix from the js source code, but I can't find where to fix it.

So I just add comment.

[YuriGor]

Hi, thank you for PR.
parent arg should not be IDeepEntry.
findDeep returns same set of data as passing into iteratee
Here is a docs:
https://deepdash.io/#iteratee
"parentValue - an object or an array which contains current value"