Update de-de.json

Author: mhadica

src/locale/de-de.json

@@ -11,7 +11,7 @@
         "freeHighlight": "Hervorheben",
         "freeText": "Text",
         "signature": "Unterschrift",
-        "stamp": "Stempe",
+        "stamp": "Stempel",
         "note": "Notiz",
         "arrow": "Pfeil",
         "cloud": "Wolke",