clippy fix and make perf warnings to errors

asyncgit/src/lib.rs

@@ -5,6 +5,7 @@
 #![deny(clippy::all)]
 #![deny(clippy::unwrap_used)]
 #![deny(clippy::panic)]
+#![deny(clippy::perf)]
 
 pub mod cached;
 mod commit_files;

scopetime/src/lib.rs

@@ -3,6 +3,7 @@
 #![forbid(unsafe_code)]
 #![forbid(missing_docs)]
 #![deny(clippy::unwrap_used)]
+#![deny(clippy::perf)]
 
 use std::time::Instant;
 

src/keys.rs

@@ -216,7 +216,7 @@ pub fn get_hint(ev: KeyEvent) -> String {
         KeyCode::F(u) => {
             format!("{}F{}", get_modifier_hint(ev.modifiers), u)
         }
-        KeyCode::Null => get_modifier_hint(ev.modifiers).to_string(),
+        KeyCode::Null => get_modifier_hint(ev.modifiers),
     }
 }
 

src/main.rs

@@ -1,6 +1,7 @@
 #![forbid(unsafe_code)]
 #![deny(clippy::cargo)]
 #![deny(clippy::pedantic)]
+#![deny(clippy::perf)]
 #![deny(clippy::nursery)]
 #![deny(clippy::unwrap_used)]
 #![deny(clippy::panic)]