Fix Writer losing text when Title contains a TextRun instead a string.

src/PhpWord/Writer/HTML/Element/Title.php

@@ -45,7 +45,7 @@ class Title extends AbstractElement
                 $text = $this->escaper->escapeHtml($text);
             }
         } elseif ($text instanceof \PhpOffice\PhpWord\Element\AbstractContainer) {
-            $writer = new Container($this->parentWriter, $this->element);
+            $writer = new Container($this->parentWriter, $text);
             $text = $writer->write();
         }
 

tests/PhpWord/Writer/HTML/ElementTest.php

@@ -18,6 +18,7 @@
 namespace PhpOffice\PhpWord\Writer\HTML;
 
 use PhpOffice\PhpWord\Element\Text as TextElement;
+use PhpOffice\PhpWord\Element\TextRun;
 use PhpOffice\PhpWord\Element\TrackChange;
 use PhpOffice\PhpWord\PhpWord;
 use PhpOffice\PhpWord\Writer\HTML;
@@ -138,4 +139,22 @@ class ElementTest extends \PHPUnit\Framework\TestCase
 
         return $dom;
     }
+
+    public function testWriteTitleTextRun()
+    {
+        $expected = 'Title with TextRun';
+
+        $phpWord = new PhpWord();
+        $section = $phpWord->addSection();
+
+        $textRun = new TextRun();
+        $textRun->addText($expected);
+
+        $section->addTitle($textRun);
+
+        $htmlWriter = new HTML($phpWord);
+        $content = $htmlWriter->getContent();
+
+        $this->assertTrue(strpos($content, $expected) !== false);
+    }
 }