Fix parsing of hex encoded escaped bytes

crates/uplc/src/parser.rs

@@ -232,6 +232,7 @@ peg::parser! {
           / "\\\"" { '\"' } // double quote
           / "\\'"  { '\'' } // single quote
           / "\\\\" { '\\' } // backslash
+          / "\\x" i:character() i2:character() { hex::decode([i, i2].iter().collect::<String>()).unwrap()[0].into() }
           / [ ^ '"' ]
           / expected!("or any valid ascii character")
 

crates/uplc/src/pretty.rs

@@ -281,7 +281,7 @@ impl Constant {
                         .collect(),
                 )
                 .unwrap(),
-            )),
+            )) .append(RcDoc::text("\"")),
             Constant::Unit => RcDoc::text("()"),
             Constant::Bool(b) => RcDoc::text(if *b { "True" } else { "False" }),
             Constant::ProtoList(_, items) => RcDoc::text("[")