Remind comments within a thread to the top of their relative level
Every level of comment will let the user remind a comment to the top of it.
e.g. L0, L1, L2 comments can all be reminded to the top of their related level (L0 to 0, only).
This is a Minds Plus feature.
Limit: one remind per phone number verified user, per comment. Otherwise, error: You already reminded this comment.