Allow notifications when a post is edited

[JKSH]

Currently, we can receive notifications when:

1. A watched thread gets a new post (All regular users)
2. A post gets flagged (Moderators)

However, I couldn't find a way to way to enable notifications when one these posts gets edited.

Use Cases

1. When a post is edited to add new content, the topic's watchers might want to know.
2. When a spammer edits an existing post to insert a spam link, the moderators probably want to know.

Optional Functionality

To prevent this from getting too noisy, we could have:

• The ability to opt in/out of edit notifications
• "Batching" of edit notifications -- For example, if a post was edited multiple times within 5 minutes, only the last one is highlighted

[quokka]

+1 for this

[baris]

https://github.com/NodeBB/NodeBB/issues/8308

[quokka]

@baris

Thanks. That's awesome that you put that in so quickly!