Add link + misc typo correction

Former-commit-id: 0f15c3a3

GTSRB/03-Tracking-and-visualizing.ipynb

@@ -302,10 +302,10 @@
     "## Step 5 - Prepare callbacks  \n",
     "We will add 2 callbacks :  \n",
     " - **TensorBoard**  \n",
-    "  Training logs, which can be visualised using Tensorboard tool.  \n",
+    "  Training logs, which can be visualised using [Tensorboard tool](https://www.tensorflow.org/tensorboard).  \n",
     "  Launch a terminal directly through the Jupyter interface (click on Menu button "File -> New -> Terminal").\n",
     "  Check directory and go to directory \n",
-    "  # cd \n",
+    "  `# cd `\n",
     "  Then launch \n",
     "    - `# tensorboard_launch --logdir ./run/logs` if using a Gricad node\n",
     "    - `# tensorboard --logdir ./run/logs` if using your own workstation\n",