Add Parameter retitleIfNeeded to AddSheet

A little more useful than my first crack at this.

Author: oleibman

src/PhpSpreadsheet/Spreadsheet.php

@@ -515,16 +515,7 @@ public function createSheet(?int $sheetIndex = null): Worksheet
     {
         $newSheet = new Worksheet($this);
         $title = $newSheet->getTitle();
-        if ($this->sheetNameExists($title)) {
-            $i = 1;
-            $newTitle = "$title $i";
-            while ($this->sheetNameExists($newTitle)) {
-                ++$i;
-                $newTitle = "$title $i";
-            }
-            $newSheet->setTitle($newTitle);
-        }
-        $this->addSheet($newSheet, $sheetIndex);
+        $this->addSheet($newSheet, $sheetIndex, true);
 
         return $newSheet;
     }
@@ -545,8 +536,20 @@ public function sheetNameExists(string $worksheetName): bool
      * @param Worksheet $worksheet The worksheet to add
      * @param null|int $sheetIndex Index where sheet should go (0,1,..., or null for last)
      */
-    public function addSheet(Worksheet $worksheet, ?int $sheetIndex = null): Worksheet
+    public function addSheet(Worksheet $worksheet, ?int $sheetIndex = null, bool $retitleIfNeeded = false): Worksheet
     {
+        if ($retitleIfNeeded) {
+            $title = $worksheet->getTitle();
+            if ($this->sheetNameExists($title)) {
+                $i = 1;
+                $newTitle = "$title $i";
+                while ($this->sheetNameExists($newTitle)) {
+                    ++$i;
+                    $newTitle = "$title $i";
+                }
+                $worksheet->setTitle($newTitle);
+            }
+        }
         if ($this->sheetNameExists($worksheet->getTitle())) {
             throw new Exception(
                 "Workbook already contains a worksheet named '{$worksheet->getTitle()}'. Rename this worksheet first."