fix: remove dead code when setting the subject (#757)

After a check for type string there is no way to pass in an object of type subject
so this check is dead code and can be removed.
Also fixed some minor spelling and codestyle issues in the file

lib/mail/EmailAddress.php

@@ -25,7 +25,9 @@ class EmailAddress implements \JsonSerializable
     private $name;
     /** @var $email string The email address */
     private $email;
-    /** @var $substitutions Substitution[] An array of key/value substitutions to be be applied to the text and html content of the email body */
+    /** @var $substitutions Substitution[] An array of key/value substitutions
+     * to be be applied to the text and html content of the email body
+     */
     private $substitutions;
     /** @var $subject Subject The personalized subject of the email */
     private $subject;
@@ -40,6 +42,7 @@ class EmailAddress implements \JsonSerializable
      *                                   be be applied to the text and html content
      *                                   of the email body
      * @param string|null $subject The personalized subject of the email
+     * @throws TypeException
      */
     public function __construct(
         $emailAddress = null,
@@ -65,9 +68,8 @@ public function __construct(
      * Add the email address to a EmailAddress object
      *
      * @param string $emailAddress The email address
-     * 
      * @throws TypeException
-     */ 
+     */
     public function setEmailAddress($emailAddress)
     {
         if (!(is_string($emailAddress) &&
@@ -104,9 +106,8 @@ public function getEmail()
      * Add a name to a EmailAddress object
      *
      * @param string $name The name of the person associated with the email
-     * 
      * @throws TypeException
-     */ 
+     */
     public function setName($name)
     {
         if (!is_string($name)) {
@@ -125,13 +126,13 @@ public function setName($name)
             Double quotes will be shown in some email clients, so the name should
             only be wrapped when necessary.
         */
-        // Only wrapp in double quote if comma or semicolon are found
+        // Only wrap in double quote if comma or semicolon are found
         if (false !== strpos($name, ',') || false !== strpos($name, ';')) {
             // Unescape quotes
             $name = stripslashes(html_entity_decode($name, ENT_QUOTES));
             // Escape only double quotes
             $name = str_replace('"', '\\"', $name);
-            // Wrapp in double quotes
+            // Wrap in double quotes
             $name = '"' . $name . '"';
         }
         $this->name = (!empty($name)) ? $name : null;
@@ -153,9 +154,8 @@ public function getName()
      * @param array $substitutions An array of key/value substitutions to
      *                             be be applied to the text and html content
      *                             of the email body
-     * 
      * @throws TypeException
-     */ 
+     */
     public function setSubstitutions($substitutions)
     {
         if (!is_array($substitutions)) {
@@ -177,23 +177,19 @@ public function getSubstitutions()
      * Add a subject to a EmailAddress object
      *
      * @param string $subject The personalized subject of the email
-     * 
      * @throws TypeException
-     */ 
+     */
     public function setSubject($subject)
     {
         if (!is_string($subject)) {
             throw new TypeException('$subject must be of type string.');
         }
-        if (!($subject instanceof Subject)) {
-            $this->subject = new Subject($subject);
-        } else {
-            $this->subject = $subject;
-        }
+        // Now that we know it is a string, we can safely create a new subject
+        $this->subject = new Subject($subject);
     }
 
     /**
-     * Retrieve a subject from a EmailAddress object
+     * Retrieve a subject from an EmailAddress object
      *
      * @return Subject
      */
@@ -203,7 +199,7 @@ public function getSubject()
     }
 
     /**
-     * Return an array representing a EmailAddress object for the Twilio SendGrid API
+     * Return an array representing an EmailAddress object for the Twilio SendGrid API
      *
      * @return null|array
      */