Merge pull request #732 from robbieaverill/patch-1

Fix "get single label" example and add correct example for getting issue's labels

Author: acrobat

doc/issue/labels.md

@@ -15,7 +15,7 @@ Returns an array of project labels.
 ### Get a single label
 
 ```php
-$label = $client->api('issue')->labels()->all('KnpLabs', 'php-github-api', 'label1');
+$label = $client->api('issue')->labels()->show('KnpLabs', 'php-github-api', 'label1');
 ```
 
 ### Create a label
@@ -57,6 +57,12 @@ Add a label to the issue by username, repo, issue number label name and. If the
 the system, it will be created.
 Returns an array of the issue labels.
 
+### Get all labels for an issue
+
+```php
+$label = $client->api('issue')->labels()->all('KnpLabs', 'php-github-api', 4);
+```
+
 ### Replace all labels for an issue
 
 > Requires [authentication](../security.md).