Added new constant to russian language

Author: Mykola Nicholas

src/PhpWord/Style/Language.php

@@ -70,6 +70,9 @@ final class Language extends AbstractStyle
 
     const UK_UA = 'uk-UA';
     const UK_UA_ID = 1058;
+    
+    const RU_RU = 'ru-RU';
+    const RU_RU_ID = 1049;
 
     /**
      * Language ID, used for RTF document generation