The pinout of that SR is clearly shown but I admit the schematic could be a bit confusing for a beginner. Regardless it should have pin numbers on the schematic, without them it's really just a block diagram.
I've sent an e-mail to massimo banzi & david cuartielles
After all this time and probably a 1000 people using that stupid cap and another 1000 people highlighting the error, good luck
Still it's possible that despite that nobody has actually emailed them after all this time because we assumed the problem would be noticed.
This is probably one of the most popular playground pages, every man and his dog uses it when first playing with shiftOut(), and it has a bad error.
It should be fixed.