Make use of is_iterable and is_countable functions

Doing searches for $value instanceof \Traversable and instanceof \Countable; and checking if they're also checking is_array, believe all have been addressed.

Left a comment but I would +1 for deprecating that one function since it does 1 thing now.

Added some suggestions to the MR.

Deprecated Inspector::assertTraversable and added a change record. Applied both suggestions.

Left some comments on MR about the CR link.

But checked that the replacements were done. Probably good to self RTBC @mstrelan after the link updates.

Fixed the link to the CR, back to RTBC

Committed and pushed c506000f20 to 11.x and 8b6fd70a73 to 10.3.x. Thanks!

Automatically closed - issue fixed for 2 weeks with no activity.