TotalItems: count MUST be exact: propose to SHOULD

[bjdmeest]

TotalItems are very important, e.g. for UX.
However, It can be very hard to always exactly calculate that totalItems numbers.
Propose: change phrasing "The totalItems property in the response body MUST reflect the total number of items across all pages" to "The totalItems property in the response body SHOULD reflect the total number of items across all pages"

[renyuneyun]

What about this sentence:

Deletion and Containment: When a resource is deleted, the server MUST atomically remove it from its parent container's items list. The parent container's totalItems count and ETag MUST be updated accordingly.

It did not mention when this must happen. I guess that's deliberate? Will there be any unexpected situations?

[elf-pavlik]

Resolved in #157