Apply Prettier to the entire project

This ensures that our tests will be formatted by Prettier, among other things.

tsconfig.json

@@ -18,7 +18,7 @@
     ]
   },
   "include": [
-    "./src/**/*.ts", 
+    "./src/**/*.ts",
     "./src/**/*.tsx",
     "./test/**/*.ts",
     "./test/**/*.tsx"