Fix `puppet-master` example not working if `puppet::set_data` returns a non-unit type in the PDAs section (#103)

src/anchor_in_depth/PDAs.md

@@ -271,7 +271,8 @@ mod puppet_master {
         puppet::cpi::set_data(
             ctx.accounts.set_data_ctx().with_signer(&[&[bump][..]]),
             data,
-        )
+        )?;
+        Ok(())
     }
 }