Welcome to Connect, @ymustuknow. In answer to your question about whether you can eat chocolate pudding the day before your colonoscopy is that it’s not recommended.

In order to thoroughly prepare the colon so that it’s squeaky clean for a colonoscopy the process begins many days before the procedure.

Five days prior, it’s recommended to switch to a low fiber diet.
The last 1-3 days, depending on instructions from the doctor, patients are limited to liquids, broths, jello.
That means:
no dairy products, including milk, smoothies or shakes
no orange, grapefruit, or prune juice
no red or purple juices or any liquids that people are unable to see through.

You can eat canned fruits such as peaches but no fruits with a peel. So that would leave out grapes unless they are peeled.

Here’s a great article from medicalnewstoday.com which should answer your questions about what you can consume during the days preceding your colonoscopy.
https://www.medicalnewstoday.com/articles/what-to-eat-to-prepare-for-a-colonoscopy
Hopefully you saw this in time! When is your colonoscopy scheduled?