Fix slide definition, there was not transistion / slide seperation

04 - Working with NumPy arrays.ipynb

@@ -757,7 +757,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Explicitely specifying the data type\n",
+      "Explicitly specifying the data type\n",
       "---"
      ]
     },
@@ -887,7 +887,7 @@
      "cell_type": "markdown",
      "metadata": {
       "slideshow": {
-       "slide_type": "-"
+       "slide_type": "subslide"
       }
      },
      "source": [