clean: bad whitespace and Flow types in extractErrors

- whitespace errors in extractErrors
- unnecessary Flow comments in invertObject when we're using TS
  - also inconsistent, it looks like they've been removed and replaced
    with TS elsewhere
    - here TS types were added but Flow was also left in

src/errors/extractErrors.ts

@@ -112,7 +112,7 @@ function ErrorDev(message) {
   return error;
 }
 
-export default ErrorDev;      
+export default ErrorDev;
       `,
       'utf-8'
     );

src/errors/invertObject.ts

@@ -16,9 +16,7 @@
 
 type Dict = { [key: string]: any };
 
-export function invertObject(
-  targetObj: Dict /* : ErrorMap */
-) /* : ErrorMap */ {
+export function invertObject(targetObj: Dict) {
   const result: Dict = {};
   const mapKeys = Object.keys(targetObj);