... like "bug21" in message bodies.

There's a standard notation everyone uses for
Bugzilla bugs -- "#3113" means bug number 3113. 
Knowing this, the Bugzilla developers have a
dirty-but-effective kluge where anything matching
the regexp '<whitespace|punctuation>#[0-9]+'
occuring in a message body gets converted into a
hyperlink to that bug when displayed on the web. 
This way you can just mention a bug number, and
things will be automatically linked.

We also have a nice notation for bugs etc. --
bug31, msg106, etc. These should be scanned for
and converted into links.


Another clever thing that we should steal from
bugzilla is that when they render bugs (and I
suppose in our case, tasks too) with these
auto-links, they put strikeout through them if
they're closed already.  I would never have
thought of this, but it turns out to be very
effective and useful.



I'm 'upstreaming' this from  http://issues.fresco.org/bug32