csvpy: add link to homepage

pages/common/csvpy.md

@@ -2,6 +2,7 @@
 
 > Loads a CSV file into a Python shell.
 > Included in csvkit.
+> More information: <https://csvkit.readthedocs.io/en/latest/scripts/csvpy.html>.
 
 - Load a CSV file into a `CSVKitReader` object: