Update crates/cfg/src/cfg_expr.rs

Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

crates/cfg/src/cfg_expr.rs

@@ -44,7 +44,7 @@ impl fmt::Display for CfgAtom {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             CfgAtom::Flag(name) => write!(f, "{}", name),
-            CfgAtom::KeyValue { key, value } => write!(f, "{} = \"{}\"", key, value),
+            CfgAtom::KeyValue { key, value } => write!(f, "{} = {:?}", key, value),
         }
     }
 }