empty translations in ts file

and if empty in qm file take source value

Author: signedav

src/core/qgsproject.cpp

@@ -2834,5 +2834,11 @@ QString QgsProject::translate( const QString &context, const QString &sourceText
     return sourceText;
   }
 
-  return mTranslator->translate( context.toUtf8(), sourceText.toUtf8(), disambiguation, n );
+  QString result = mTranslator->translate( context.toUtf8(), sourceText.toUtf8(), disambiguation, n );
+
+  if ( result.isEmpty() )
+  {
+    return sourceText;
+  }
+  return result;
 }

src/core/qgstranslationcontext.cpp

@@ -81,8 +81,7 @@ void QgsTranslationContext::writeTsFile( const QString &locale )
     messageElement.appendChild( sourceElement );
 
     QDomElement translationElement = doc.createElement( QStringLiteral( "translation" ) );
-    QDomText translationText = doc.createTextNode( translatableObject.source );
-    translationElement.appendChild( translationText );
+    translationElement.setAttribute( QStringLiteral( "type" ), QStringLiteral( "unfinished" ) );
     messageElement.appendChild( translationElement );
   }