fix(clippy): fix derivable_impls

 See
 https://rust-lang.github.io/rust-clippy/master/index.html#derivable_impls

src/api/search.rs

@@ -45,20 +45,15 @@ struct Document {
     highlight: elastic::ResponseHighlight,
 }
 
-#[derive(Deserialize)]
+#[derive(Deserialize, Default)]
 #[serde(rename_all = "lowercase")]
 enum Sort {
+    #[default]
     Best,
     Relevance,
     Popularity,
 }
 
-impl Default for Sort {
-    fn default() -> Self {
-        Sort::Best
-    }
-}
-
 #[derive(Deserialize)]
 struct Params {
     q: String,