Document that comment statistics only update when a new comment is created, not when an old comment is updated.

Problem/Motivation

The comment statistics for a node are updated only when a new comment is created, or when the most recent comment is updated. When an older comment is updated there is no change to the comment statistics.

This may cause some confusion, but is logical, you don't want an item to appear updated every time someone updates an old comment.

Steps to reproduce

N/A

Proposed resolution

Update documentation to note that the last comment timestamp only considers comment creation, and does not take updates to old comments into account

Remaining tasks

Start a new patch that updates documentation only.

User interface changes

None