Added "Further reading" section

mpoulin · web-flow · commit 86f84b26b879 · 2018-09-06T14:53:46.000-06:00
diff --git a/docs/writing/string_formatting.rst b/docs/writing/string_formatting.rst
@@ -9,3 +9,7 @@ Intermedate formatting
 
 Advanced formatting
 -------------------
+
+Further reading
+---------------
+
