fix: clippy warnings for hexadecimal and octal conversions vice versa

Author: NithinU2802

src/conversions/hexadecimal_to_octal.rs

@@ -12,7 +12,7 @@ pub fn hexadecimal_to_octal(hex_str: &str) -> Result<String, &'static str> {
     }
 
     // Validate hexadecimal string
-    if !hex_str.chars().all(|c| c.is_digit(16)) {
+    if !hex_str.chars().all(|c| c.is_ascii_hexdigit()) {
         return Err("Invalid hexadecimal string");
     }
 

src/conversions/octal_to_hexadecimal.rs

@@ -25,7 +25,7 @@ pub fn octal_to_hexadecimal(octal_str: &str) -> Result<String, &'static str> {
     }
 
     // Convert decimal to hexadecimal
-    Ok(format!("{:X}", decimal))
+    Ok(format!("{decimal:X}"))
 }
 
 #[cfg(test)]