Adding setNumId method for ListItem style

By allowing to set the numId in the ListItem style manually, you can separate lists. Every ListItem with the same numId belongs to one list. This allows you to restart list counting.

Author: eweso

src/PhpWord/Style/ListItem.php

@@ -11,7 +11,7 @@
  * contributors, visit https://github.com/PHPOffice/PHPWord/contributors.
  *
  * @see         https://github.com/PHPOffice/PHPWord
- * @copyright   2010-2018 PHPWord contributors
+ * @copyright   2010-2017 PHPWord contributors
  * @license     http://www.gnu.org/licenses/lgpl.txt LGPL version 3
  */
 
@@ -139,6 +139,16 @@ public function getNumId()
         return $this->numId;
     }
 
+    /**
+     * Set numbering Id, to force list to restart counting. Same num id means same list
+     * @param int
+     */
+    public function setNumId($numInt)
+    {
+        $this->numId = $numInt;
+        $this->getListTypeStyle();
+    }
+
     /**
      * Get legacy numbering definition
      *
@@ -148,7 +158,12 @@ public function getNumId()
     private function getListTypeStyle()
     {
         // Check if legacy style already registered in global Style collection
-        $numStyle = "PHPWordList{$this->listType}";
+        $numStyle = "PHPWordList_" . $this->listType;
+        
+        if ($this->numId) {
+            $numStyle .= '_' . $this->numId;
+        }
+        
         if (Style::getStyle($numStyle) !== null) {
             $this->setNumStyle($numStyle);