Pudding should now be less messy

Fixed "the proof is in the pudding" to "the proof of the pudding". The phrase is: "The proof of the pudding is in the eating." That's how you know it's pudding. If the proof would be in the pudding, it would just be messy.

Author: route92

part1.asciidoc

@@ -60,7 +60,7 @@ Three appendices are further explorations of the content from Part I:
   code: how we build and run the Docker images, where we manage configuration
   info, and how we run different types of tests.
 
-* <<appendix_csvs>> is a "proof is in the pudding" kind of content, showing
+* <<appendix_csvs>> is a "proof of the pudding" kind of content, showing
   how easy it is to swap out our entire infrastructure--the Flask API, the
   ORM, and Postgres—for a totally different I/O model involving a CLI and
   CSVs.