add link to commit history

Author: Tom-van-Woudenberg

book/08/sympy.ipynb

@@ -44,8 +44,8 @@
     "````{margin}\n",
     "```{attributiongrey} Attribution\n",
     ":class: attribution\n",
-    "Written by Tom van Woudenberg\n",
-    " \n",
+    "Written by [Tom van Woudenberg](https://github.com/TeachBooks/learn-python/commits/MUDE_book/book/08/sympy.ipynb)\n",
+    "\n",
     "This page reuses CC BY content from {cite:t}`sympy`. {fa}`quote-left`[Find out more here](external_resources)\n",
     "```\n",
     "````\n",