Fix reference to tracer from Tracer

Author: fluidnumericsJoe

docs/user_guide/examples/tutorial_interpolation.ipynb

@@ -329,11 +329,11 @@
     "\n",
     "\n",
     "def SampleTracer_Node(particles, fieldset):\n",
-    "    particles.Tracer = fieldset.T_node[particles]\n",
+    "    particles.tracer = fieldset.T_node[particles]\n",
     "\n",
     "\n",
     "def SampleTracer_Face(particles, fieldset):\n",
-    "    particles.Tracer = fieldset.T_face[particles]"
+    "    particles.tracer = fieldset.T_face[particles]"
    ]
   },
   {
@@ -370,7 +370,7 @@
     "    SampleTracer_Face,\n",
     "    runtime=np.timedelta64(1, \"D\"),\n",
     "    dt=np.timedelta64(1, \"D\"),\n",
-    "    verbose_progress=Falsex,\n",
+    "    verbose_progress=False,\n",
     ")"
    ]
   },