Reduce nesting in if blocks by short circuiting

src/less.rs

@@ -11,13 +11,13 @@ pub fn retrieve_less_version(less_path: &dyn AsRef<OsStr>) -> Option<usize> {
 }
 
 fn parse_less_version(output: &[u8]) -> Option<usize> {
-    if output.starts_with(b"less ") {
-        let version = std::str::from_utf8(&output[5..]).ok()?;
-        let end = version.find(|c: char| !c.is_ascii_digit())?;
-        version[..end].parse::<usize>().ok()
-    } else {
-        None
+    if !output.starts_with(b"less ") {
+        return None;
     }
+
+    let version = std::str::from_utf8(&output[5..]).ok()?;
+    let end = version.find(|c: char| !c.is_ascii_digit())?;
+    version[..end].parse::<usize>().ok()
 }
 
 #[test]