jQuery: added typing for fn
jQuery: JSDoc Callbacks and tighten up typing
jQuery: back
jQuery: cater for jQuery.clientSideLogging

I haven't looked in detail at this but it looks that
jQuery.clientSideLogging is ill-advisedly clobbering ```$.error```.
This should probable be addressed at some point.
Merge pull request #1588 from johnnyreilly/master

jQuery: JSDoc Callbacks and tighten up typing