mutable vars update

challenges/mutable-variables/description.md

@@ -9,22 +9,24 @@ In this challenge, you will declare and use **mutable variables in Rust**. You w
 In this challenge, you need to declare one mutable variable inside the function using the `let mut` keyword:
 
 - `text` with an initial value of `"hello"`
-- Print it to the console using the `println!` macro.
+- Print exactly `"Text is hello"` to the console using the `println!` macro.
 - Mutate the variable to `"bye"`.
-- Print the variable again to the console using the `println!` macro.
+- Print exactly `"Text is bye"` to the console using the `println!` macro.
 - Return the final value of the variable.
 
 ### Println! Macro
 
 The `println!` macro is used to print text to the console. It is similar to the `println` function in other programming languages. The `println!` macro is used to print formatted text to the console.
 
 ```rust
-println!("Hello, World!");
+let text = "hello";
+println!("Text is {}", text);
 ```
 
+The `{}` is a placeholder that will be replaced by the value of the variable `text`.
+
 ## Hints
 
 - Use the `let mut` keyword to declare a mutable variable.
 - Reassign the variable directly by using the `=` operator.
 - Ensure to return the final value of the variable from the function.
-- Use `println!` statements to debug and check the values during reassignment.

challenges/mutable-variables/src/lib.rs

@@ -1,11 +1,11 @@
 pub fn mutating_variables() -> &'static str {
     let mut text = "hello";
 
-    println!("Text is: {}", text);
+    println!("Text is {}", text);
 
     text = "bye";
 
-    println!("Text is: {}", text);
+    println!("Text is {}", text);
 
     text
 }

challenges/mutable-variables/tests/tests.rs

@@ -56,12 +56,12 @@ mod tests {
 
         match &macros[..] {
             [first, second] => {
-                // First macro should be println!("Text is: {}", "hello");
+                // First macro should be println!("Text is {}", "hello");
                 assert_eq!(first.tokens.len(), 3);
                 // will have 3 tokens: &str, , and "hello"
                 match &first.tokens[..] {
                     [text_is, _comma, text] => {
-                        assert_eq!(text_is, "\"Text is: {}\"");
+                        assert_eq!(text_is, "\"Text is {}\"");
                         assert_eq!(
                             text, "text",
                             "Expected text variable to be used in println!"
@@ -75,12 +75,12 @@ mod tests {
                     }
                 }
 
-                // Second macro should be println!("Text is: {}", "bye");
+                // Second macro should be println!("Text is {}", "bye");
                 assert_eq!(second.tokens.len(), 3);
                 // will have 3 tokens: &str, , and "bye"
                 match &second.tokens[..] {
                     [text_is, _comma, bye] => {
-                        assert_eq!(text_is, "\"Text is: {}\"");
+                        assert_eq!(text_is, "\"Text is {}\"");
                         assert_eq!(bye, "text", "Expected text variable to be used in println!");
                     }
                     _ => {