Apply clippy's suggestion

- Replace `Box::new(T::default())` with `Box::default()`.
- Allow `needless_borrow` in intentional test cases.

Author: SpriteOvO

spdlog/examples/05_custom_formatter.rs

@@ -66,7 +66,7 @@ fn impl_manually() {
     }
 
     // Building a custom formatter.
-    let new_formatter: Box<MyFormatter> = Box::new(MyFormatter::default());
+    let new_formatter: Box<MyFormatter> = Box::default();
 
     // Setting the new formatter for each sink of the default logger.
     for sink in spdlog::default_logger().sinks() {

spdlog/src/formatter/pattern_formatter/mod.rs

@@ -1249,11 +1249,13 @@ pub mod tests {
 
     #[test]
     fn test_pattern_ref_as_pattern() {
+        #[allow(clippy::needless_borrow)]
         test_pattern(&String::from("literal"), "literal", None);
     }
 
     #[test]
     fn test_pattern_mut_as_pattern() {
+        #[allow(clippy::needless_borrow)]
         test_pattern(&mut String::from("literal"), "literal", None);
     }