Merge pull request jerry-git#6 from vivek28111992/patch-1

Store the return value of str.replace

Author: jerry-git

notebooks/beginner/strings.ipynb

@@ -92,7 +92,7 @@
  "metadata": {},
  "outputs": [],
  "source": [
- "my_string.replace('a', '?')\n",
+ "my_string = my_string.replace('a', '?')\n",
  "print(my_string)"
  ]
  },