Fix typos in contributing guide

Three sentences, two typos. A new record!

Author: Eric Sorenson

CONTRIBUTING.md

@@ -98,7 +98,7 @@ This repository includes [a list of the most-used GitHub topics that don't yet h
 
 ## Guidelines
 
-* Avoid conflicts of interest. These should be of general community interest, not a marketing vehicle for a product or a personal prorject. If you are a direct employee of a company creating the project, or the createor and sole maintainer, it's unlikely to be accepted.
+* Avoid conflicts of interest. These should be of general community interest, not a marketing vehicle for a product or a personal project. If you are a direct employee of a company creating the project, or the creator and sole maintainer, it's unlikely to be accepted.
 
 ## Running tests