Feature request: bridge spoilers to IRC by sending them with the same background&foreground colour (and that to Matrix as spoiler)

[Mikaela]

Is your feature request related to a problem? Please describe.

Matrix supports spoilers which are a feature I often find myself missing on rooms bridged to IRC.

Describe the solution you'd like

It's a documented practice on IRC to send spoilers with the same foreground and background text. Thus I would like that case to be bridged to Matrix as a spoiler too.

Describe alternatives you've considered

IRCv3 has discussion on the subject at ircv3/ircv3-ideas#33 where the previous case is often mentioned.

Additional context

Spoilers are part of the Matrix specification since version 1.1.