Writing a Widget Using Cairo typo

[jim Pharis <binbrain gmail com>]

I noticed the ever so smallest of typo's in the article Writing a
Widget Using Cairo.

 #define EGG_IS_CLOCK_FACE_CLASS(obj)    (G_TYPE_CHECK_CLASS_TYPE
((obj), EFF_TYPE_CLOCK_FACE))

EFF should be EGG

Not a big deal but somebody that tries to copy and paste this macro
might run into a problem.

--
- Jim Pharis