Implement Display for ObjectPath

Seems natural since it's just a thin wrapper around String.

Let's us do `format!("Object path {path}")` instead of
`format!("Object path {}", path.as_str())` which is handy for logging in
particular.

Author: swsnr

glib/src/variant.rs

@@ -106,6 +106,7 @@ use std::{
     cmp::Ordering,
     collections::{BTreeMap, HashMap},
     fmt,
+    fmt::Display,
     hash::{BuildHasher, Hash, Hasher},
     mem, ptr, slice, str,
 };
@@ -2021,6 +2022,12 @@ impl ObjectPath {
     }
 }
 
+impl Display for ObjectPath {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
 impl std::ops::Deref for ObjectPath {
     type Target = str;