doc: fix code examples in url.md

* Update outputs.
* Refine spaces.
* Restore missing part.

PR-URL: https://github.com/nodejs/node/pull/13288
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

doc/api/url.md

@@ -186,6 +186,7 @@ console.log(myURL.href);
   // Prints https://example.org/foo
 
 myURL.href = 'https://example.com/bar';
+console.log(myURL.href);
   // Prints https://example.com/bar
 ```
 
@@ -332,7 +333,7 @@ console.log(myURL.protocol);
 
 myURL.protocol = 'ftp';
 console.log(myURL.href);
-  // Prints ftp://example.org
+  // Prints ftp://example.org/
 ```
 
 Invalid URL protocol values assigned to the `protocol` property are ignored.
@@ -380,7 +381,7 @@ console.log(myURL.username);
 
 myURL.username = '123';
 console.log(myURL.href);
-  // Prints https://123:xyz@example.com
+  // Prints https://123:xyz@example.com/
 ```
 
 Any invalid URL characters appearing in the value assigned the `username`
@@ -571,7 +572,8 @@ console.log(params.toString());
 new URLSearchParams([
   ['user', 'abc', 'error']
 ]);
-  // Throws TypeError: Each query pair must be a name/value tuple
+  // Throws TypeError [ERR_INVALID_TUPLE]:
+  //        Each query pair must be an iterable [name, value] tuple
 ```
 
 #### urlSearchParams.append(name, value)
@@ -817,7 +819,7 @@ console.log(myURL.toString());
   // Prints https://a:b@xn--6qqa088eba/?abc#foo
 
 console.log(url.format(myURL, { fragment: false, unicode: true, auth: false }));
-  // Prints 'https://你好你好?abc'
+  // Prints 'https://你好你好/?abc'
 ```
 
 ## Legacy URL API