refactor with clippy

src/display.rs

@@ -9,17 +9,20 @@ struct Token {
     children: bool,
 }
 
-impl ToString for Token {
-    fn to_string(&self) -> String {
+impl Display for Token {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         let Token { siblings, children } = self;
 
-        match (siblings, children) {
-            (true, true) => "│   ",
-            (true, false) => "├── ",
-            (false, true) => "    ",
-            (false, false) => "└── ",
-        }
-        .to_string()
+        write!(
+            f,
+            "{}",
+            match (siblings, children) {
+                (true, true) => "│   ",
+                (true, false) => "├── ",
+                (false, true) => "    ",
+                (false, false) => "└── ",
+            }
+        )
     }
 }
 
@@ -50,7 +53,7 @@ impl Display for Indentation {
         let first: usize = if self.ignore_root { 1 } else { 0 };
 
         for token in &self.tokens[first..] {
-            write!(f, "{}", token.to_string())?;
+            write!(f, "{token}")?;
         }
 
         Ok(())

src/lib.rs

@@ -733,16 +733,11 @@ impl<T: Display> Display for Tree<T> {
             match edge {
                 Edge::Open(node) if node.has_children() => {
                     indent.indent(node.next_sibling().is_some());
-                    write!(f, "{}{}\n", indent.to_string(), node.value())?;
-                }
-                Edge::Open(node) if node.next_sibling().is_some() => {
-                    indent.indent(node.next_sibling().is_some());
-                    write!(f, "{}{}\n", indent.to_string(), node.value())?;
-                    indent.deindent();
+                    writeln!(f, "{indent}{}", node.value())?;
                 }
                 Edge::Open(node) => {
                     indent.indent(node.next_sibling().is_some());
-                    write!(f, "{}{}\n", indent.to_string(), node.value())?;
+                    writeln!(f, "{indent}{}", node.value())?;
                     indent.deindent();
                 }
                 Edge::Close(node) if node.has_children() => {