Update sympy.ipynb

Author: Tom-van-Woudenberg

book/08/sympy.ipynb

@@ -43,12 +43,12 @@
    "source": [
     "# SymPy\n",
     "\n",
-    "```{admonition} Attribution\n",
+    "\n",
+    "```{attributiongrey} Attribution\n",
     ":class: attribution\n",
-    " \n",
     "Written by Tom van Woudenberg\n",
     " \n",
-    "This page reuses CC BY content from {cite:t}`sympy`. {fa}`quote-left`[Find out more here](external_resources)`\n",
+    "This page reuses CC BY content from {cite:t}`sympy`. {fa}`quote-left`[Find out more here](external_resources)\n",
     "```\n",
     "\n",
     "SymPy is a Python library for symbolic mathematics. You can use it as a tool to evaluate basic and complicated math operations, whenever they become tedious or error prone.\n",