Changed 20.7 solution

Author: mattpocock

src/04-generics-advanced/20.7-working-around-partial-inference.solution.ts

@@ -1,7 +1,7 @@
 import { Equal, Expect } from "../helpers/type-utils";
 
 export const makeSelectors =
-  <TSource = "Type argument expected in makeSelectors">() =>
+  <TSource = "makeSelectors expects to be passed a type argument">() =>
   <TSelectors extends Record<string, (source: TSource) => any>>(
     selectors: TSelectors
   ) => {