Fix dead code warning in issue 795 regression test

    warning: field is never read: `x`
     --> tests/regression/issue795.rs:9:15
      |
    9 |     Variant { x: u8 },
      |               ^^^^^
      |
      = note: `#[warn(dead_code)]` on by default

tests/regression/issue795.rs

@@ -5,7 +5,7 @@ use serde_json::json;
 use std::fmt;
 
 #[derive(Debug)]
-enum Enum {
+pub enum Enum {
     Variant { x: u8 },
 }