update doc

Author: ScriptRaccoon

CONTRIBUTING.md

@@ -112,7 +112,7 @@ When contributing new data (categories, functors, properties, implications), ple
 
 - **Counterexamples**: Ensure that at least one category does not satisfy any new property of categories that is added. If no existing category fits, add a new category that does not have the new property. The same remarks apply to properties of functors.
 
-- **Positive Properties**: Do not add negated properties to the database. For example, do not add "large" as the negation of "small". Instead, add "small" to the list of unsatisfied properties for a category. As a rule of thumb, every registered property of categories should be satisfied at least by the trivial category. Similarly, every property of functors should be satisfied at least by the identity functor.
+- **Positive Properties**: Do not add negated properties to the database. For example, do not add "large" as the negation of "small". Instead, add "small" to the list of unsatisfied properties for a category. Every registered property of categories should be satisfied at least by the trivial category. Similarly, every property of functors should be satisfied at least by the identity functor.
 
 - **Proofs for Claims**: Provide proofs for all new claims (satisfied properties, unsatisfied properties, implications, special morphisms). (We are currently working on filling in the existing ones.)