Apply Clippy lints

exercises/01_variables/variables5.rs

@@ -1,6 +1,6 @@
 fn main() {
     let number = "T-H-R-E-E"; // Don't change this line
-    println!("Spell a number: {}", number);
+    println!("Spell a number: {number}");
 
     // TODO: Fix the compiler error by changing the line below without renaming the variable.
     number = 3;

solutions/01_variables/variables5.rs

@@ -1,6 +1,6 @@
 fn main() {
     let number = "T-H-R-E-E";
-    println!("Spell a number: {}", number);
+    println!("Spell a number: {number}");
 
     // Using variable shadowing
     // https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html#shadowing

solutions/22_clippy/clippy3.rs

@@ -15,7 +15,7 @@ fn main() {
         -1, -2, -3,
         -4, -5, -6,
     ];
-    println!("My array! Here it is: {:?}", my_arr);
+    println!("My array! Here it is: {my_arr:?}");
 
     let mut my_empty_vec = vec![1, 2, 3, 4, 5];
     // `resize` mutates a vector instead of returning a new one.
@@ -27,5 +27,5 @@ fn main() {
     let mut value_b = 66;
     // Use `mem::swap` to correctly swap two values.
     mem::swap(&mut value_a, &mut value_b);
-    println!("value a: {}; value b: {}", value_a, value_b);
+    println!("value a: {value_a}; value b: {value_b}");
 }