Improve documentation.

Author: jaydenseric

readme.md

@@ -721,7 +721,7 @@ A [GraphQL cache](#graphql-instance-property-cache) map of [GraphQL operation](#
 
 ### type GraphQLCacheKey
 
-A [GraphQL cache](#type-graphqlcache) key, derived from a hash of the [`fetch` options](#type-graphqlfetchoptions) of the [GraphQL operation](#type-graphqloperation) that populated the [value](#type-graphqlcachevalue).
+A [GraphQL cache](#type-graphqlcache) key to identify a [GraphQL cache](#type-graphqlcache) [value](#type-graphqlcachevalue). Typically created by a [GraphQL cache](#type-graphqlcache) key [creator](#type-graphqlcachekeycreator) that hashes the [`fetch` options](#type-graphqlfetchoptions) of the associated [GraphQL operation](#type-graphqloperation) using [`hashObject`](#function-hashobject).
 
 **Type:** string
 

src/universal/index.js

@@ -18,10 +18,13 @@ exports.useGraphQL = require('./useGraphQL');
  */
 
 /**
- * A [GraphQL cache]{@link GraphQLCache} key, derived from a hash of the
- * [`fetch` options]{@link GraphQLFetchOptions} of the
- * [GraphQL operation]{@link GraphQLOperation} that populated the
- * [value]{@link GraphQLCacheValue}.
+ * A [GraphQL cache]{@link GraphQLCache} key to identify a
+ * [GraphQL cache]{@link GraphQLCache} [value]{@link GraphQLCacheValue}.
+ * Typically created by a [GraphQL cache]{@link GraphQLCache} key
+ * [creator]{@link GraphQLCacheKeyCreator} that hashes the
+ * [`fetch` options]{@link GraphQLFetchOptions} of the associated
+ * [GraphQL operation]{@link GraphQLOperation} using
+ * [`hashObject`]{@link hashObject}.
  * @kind typedef
  * @name GraphQLCacheKey
  * @type {string}