Use identifiers in format!

src/bin/rhai-dbg.rs

@@ -20,7 +20,7 @@ fn print_source(lines: &[String], pos: Position, offset: usize, window: (usize,
     let line = pos.line().unwrap() - 1;
     let start = if line >= window.0 { line - window.0 } else { 0 };
     let end = usize::min(line + window.1, lines.len() - 1);
-    let line_no_len = format!("{}", end).len();
+    let line_no_len = end.to_string().len();
 
     // Print error position
     if start >= end {

src/bin/rhai-repl.rs

@@ -260,7 +260,7 @@ mod sample_functions {
     /// print(result);      // prints "42 123"
     /// ```
     pub fn test(x: INT, y: INT) -> String {
-        format!("{} {}", x, y)
+        format!("{x} {y}")
     }
 
     /// This is a sample method for integers.

src/bin/rhai-run.rs

@@ -5,7 +5,7 @@ use std::{env, fs::File, io::Read, path::Path, process::exit};
 fn eprint_error(input: &str, mut err: EvalAltResult) {
     fn eprint_line(lines: &[&str], pos: Position, err_msg: &str) {
         let line = pos.line().unwrap();
-        let line_no = format!("{}: ", line);
+        let line_no = format!("{line}: ");
 
         eprintln!("{}{}", line_no, lines[line - 1]);
         eprintln!(