Update _twisted completion

["Eric P. Mangold" <teratorn@xxxxxxxxxxxx>]

Hi,

For a while now we've had a new version of the zsh tab-completion stub function. It should probably start being included in zsh, replacing the old deprecated stub function that lives at Completion/Unix/Command/_twisted.

Twisted ships a large number of commands, and e.g. `twistd' sub-commands are dynamically generated at runtime via plugin loading. As such, a static completion function is innappropriate for Twisted, and would be instantly out of date. So, the stub function just asks Twisted to send it a
completion function on stdout, which if well formed can be eval'd inside the stub function (_twisted) to produce results.

This is an improvement over the old (as exists in zsh tree, currently) stub function, which sought to locate a Twisted directory and refer to
a set of statically generated completion files that exist there (twisted/python/zsh/_* in our tree). These old stubs still exist in our tree for backward compatibility with the old stub function, and will continue to do so for a long time to come (though they are just wrappers for the new stub, now).

Please find the new stub function here, noting that it should be renamed _twisted to replace the existing one in zsh's tree,

http://twistedmatrix.com/trac/browser/trunk/twisted/python/twisted-completion.zsh

Thanks,
Eric Mangold
teratorn@xxxxxxxxxxxxxxxxx