Update comments

Author: asmsuechan

lib/Issue.js

@@ -248,10 +248,10 @@ class Issue extends Requestable {
    }
 
   /**
-   * Add label to an issue
+   * Add a label to an issue
    * @see https://developer.github.com/v3/issues/labels/#add-labels-to-an-issue
    * @param {number} issue - the id of the issue to comment on
-   * @param {string} label - the name of the label to add to the issue
+   * @param {array} label - the names of the label to add to the issue
    * @param {Requestable.callback} [cb] - will receive the status
    * @return {Promise} - the promise for the http request
    */
@@ -260,7 +260,7 @@ class Issue extends Requestable {
    }
 
   /**
-   * Add label to an issue
+   * Remove a label from an issue
    * @see https://developer.github.com/v3/issues/labels/#remove-a-label-from-an-issue
    * @param {number} issue - the id of the issue to comment on
    * @param {string} label - the name of the label to remove to the issue