fix typo

Author: lgluszek

examples/annotation_import/pdf.ipynb

@@ -126,7 +126,7 @@
         "      tool=lb.Tool.Type.NER, \n",
         "      name= \"NER\"),\n",
         "    lb.Tool( # Relationship tool given the name \"relationship\"\n",
-        "      tool=lb.Tool.Type.NER, \n",
+        "      tool=lb.Tool.Type.RELATIONSHIP, \n",
         "      name=\"relationship\")]\n",
         "    )"
       ],