Make minor grammar corrections/updates to async/promise-error-handling

Author: jchue

1-js/11-async/04-promise-error-handling/article.md

@@ -60,7 +60,7 @@ new Promise((resolve, reject) => {
 new Promise((resolve, reject) => {
 *!*
   reject(new Error("Whoops!"));
-*/!*  
+*/!*
 }).catch(alert); // Error: Whoops!
 ```
 
@@ -98,7 +98,7 @@ The final `.catch` not only catches explicit rejections, but also occasional err
 
 As we already noticed, `.catch` at the end of the chain is similar to `try..catch`. We may have as many `.then` handlers as we want, and then use a single `.catch` at the end to handle errors in all of them.
 
-In a regular `try..catch` we can analyze the error and maybe rethrow it if can't handle. The same thing is possible for promises.
+In a regular `try..catch` we can analyze the error and maybe rethrow it if it can't be handled. The same thing is possible for promises.
 
 If we `throw` inside `.catch`, then the control goes to the next closest error handler. And if we handle the error and finish normally, then it continues to the closest successful `.then` handler.