DOcument the use of spaces here
diff --git a/docs/contributing.rst b/docs/contributing.rst
index 7bb7c43..b125d1a 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -82,6 +82,15 @@
     long f(long, long,
            int *)
 
+Include a space after commas between parameters:
+
+.. code-block:: c
+
+    // Good
+    long f(int, char *)
+    // Bad
+    long f(int,char *)
+
 
 Documentation
 -------------