Add borrowing variant of CreateEmbedAuthor conversion (#3008)

Author: jamesbt365

src/builder/create_embed.rs

@@ -282,6 +282,14 @@ impl From<User> for CreateEmbedAuthor {
     }
 }
 
+#[cfg(feature = "model")]
+impl From<&User> for CreateEmbedAuthor {
+    fn from(user: &User) -> Self {
+        let avatar_icon = user.face();
+        Self::new(user.name.clone()).icon_url(avatar_icon)
+    }
+}
+
 /// A builder to create the footer data for an embed. See [`CreateEmbed::footer`]
 #[derive(Clone, Debug, Serialize)]
 #[must_use]