Handle too long messages properly

[PeeHaa]

For example at !!rfcs.

Some possible solutions:

• minify urls where it makes sense
• truncate messages (https://chat.stackoverflow.com/transcript/message/43205872#43205872)
• split over multiple messages

[DaveRandom]

There isn't a sensible generic solution to this, as message truncation is highly dependent on the content on the messages. The default should just be to error, as we currently do.

Specifically for !!rfcs I'm sure we can come up with something sensible, although remember that those messages need to not only be postable, but ideally they need to not be truncated in the star list either...

On a side note, the domain rmel.vn is currently available if you want a vanity URL shortener domain for r11 :-P

[JayPHP]

Just fix it