doc/go1.15, net/url: document new method URL.Redacted

Adds an entry in the Go1.15 release notes, but also
adds an example test for URL.Redacted.

Follow-up of CL 207082.

Updates #37419

Change-Id: Ibf81989778907511a3a3a3e4a03d1802b5dd9762
Reviewed-on: https://go-review.googlesource.com/c/go/+/227997
Run-TryBot: Emmanuel Odeke <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>

Author: odeke-em

doc/go1.15.html

@@ -134,6 +134,16 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   </dd>
 </dl>
 
+<dl id="net/url"><dt><a href="/pkg/net/url/">net/url</a></dt>
+  <dd>
+    <p><!-- CL 207082 -->
+      The new <a href="/pkg/net/url/#URL"><code>URL</code></a>
+      method <a href="/pkg/net/url/#URL.Redacted"><code>Redacted</code></a>
+      returns the URL in string form with any password replaced with <code>xxxxx</code>.
+    </p>
+  </dd>
+</dl>
+
 <dl id="pkg-runtime"><dt><a href="/pkg/runtime/">runtime</a></dt>
   <dd>
     <p><!-- CL 221779 -->

src/net/url/example_test.go

@@ -205,6 +205,21 @@ func ExampleURL_UnmarshalBinary() {
 	// https://example.org/foo
 }
 
+func ExampleURL_Redacted() {
+	u := &url.URL{
+		Scheme: "https",
+		User:   url.UserPassword("user", "password"),
+		Host:   "example.com",
+		Path:   "foo/bar",
+	}
+	fmt.Println(u.Redacted())
+	u.User = url.UserPassword("me", "newerPassword")
+	fmt.Println(u.Redacted())
+	// Output:
+	// https://user:[email protected]/foo/bar
+	// https://me:[email protected]/foo/bar
+}
+
 func ExampleURL_RequestURI() {
 	u, err := url.Parse("https://example.org/path?foo=bar")
 	if err != nil {