hide output on execution cells

Author: reint-fischer

docs/user_guide/examples/tutorial_diffusion.ipynb

@@ -257,7 +257,11 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "hide-output"
+    ]
+   },
    "outputs": [],
    "source": [
     "testParticles = get_test_particles()\n",
@@ -333,7 +337,11 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "hide-output"
+    ]
+   },
    "outputs": [],
    "source": [
     "testParticles = get_test_particles()\n",
@@ -553,7 +561,11 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {},
+   "metadata": {
+    "tags": [
+     "hide-output"
+    ]
+   },
    "outputs": [],
    "source": [
     "time = np.repeat(fieldset.time_interval.left, 13)\n",