Include more information when notifying about a subscribed label being added

Description

I subscribe to a couple labels ( gitlab-ce~2024184 , ~CI ) and I get emails when those labels are added to issues and MRs, but the emails don't have any context other than the issue/MR title, and the fact that the label has been added. Invariably I then need to click on the link to see what the issue/MR is really about. How about including more information in the original notification? The issue/MR description would probably be sufficient, although sometimes the entire thread might be needed to really have context. Sometimes that can get really long, so it might not be practical.

Note that a similar thing happens when you are first @ mentioned, but hopefully mentions have context in the comment itself, so it's less important there, and could even be distracting if the @ mention isn't really about the initial description.

Proposal

• Include issue/MR description in notifications about labels being added
• [Optional] Include the entire conversation thread

Links / references

• I believe Zendesk emails the complete conversation history on each update, and I've found that to be very useful for jumping into the middle of something, or even following up on something for the Nth time, when some time has passed in between messages.