gF finds .jade or .blade includes

Hi there mr toad, this is only my second pull request on Github.  I don't know if I am being too eager, or if this is an appropriate way to draw your attention to this contribution.  Please feel free to set me straight.

Anyway, I was really missing gF on Jade templates, until I wrote this yesterday, and I have been whizzing around my templates since then!  I don't know if there is a better implementation, it seems quite long for something so simple.  But I am finding it to be very useful.  ;)