fix: lint warnings

Author: sunng87

src/error.rs

@@ -288,7 +288,7 @@ impl From<WalkdirError> for TemplateError {
 
 fn template_segment(template_str: &str, line: usize, col: usize) -> String {
     let range = 3;
-    let line_start = if line >= range { line - range } else { 0 };
+    let line_start = line.saturating_sub(range);
     let line_end = line + range;
 
     let mut buf = String::new();

src/macros.rs

@@ -32,7 +32,6 @@
 ///  assert_eq!(&result2, "great!");
 /// # Ok(()) }
 /// ```
-
 #[macro_export]
 macro_rules! handlebars_helper {
     ($struct_name:ident: |$($name:ident: $tpe:tt$(<$($gen:ty),+>)?),*