[doc][nitpick-exceptions] Add click classes used

Currently sphinx doesn't found them for unknown reasons.

doc/nitpick-exceptions.txt

@@ -5,3 +5,8 @@ py:exc ValueError
 py:exc KeyError
 py:class tuple
 py:class list
+
+# Sphinx seems to have some issues finding click class information
+py:class click.core.Group
+py:class click.core.Command
+py:class click.core.Option