Add a warning or indicator next to messages with type "m.thread"

[rosemash]

Describe the problem

I just started using Cinny, and I almost immediately embarrassed myself by replying to messages in an active room that nobody else could see.

Describe the solution you'd like

If Cinny doesn't have any immediate intention of adding support to threads (#1349), it would be very practical to have a UI indicator beside any message that has the type "m.thread" attached to it, so you can infer that it's not visible to others.

Alternatives considered

The alternative would be adding support for threads.

Additional context

No response

[greentore]

Sounds like a good idea. Element-x is doing that.

[ajbura]

fixed in #1349