Fix clippy warnings (#2075)

Author: senekor

exercises/practice/armstrong-numbers/.meta/example.rs

@@ -1,5 +1,5 @@
 pub fn is_armstrong_number(num: u32) -> bool {
-    let s = format!("{}", num);
+    let s = format!("{num}");
     let l = s.len();
     s.chars()
         .map(|c| c.to_digit(10).unwrap().pow(l as u32))

exercises/practice/clock/.meta/example.rs

@@ -9,7 +9,7 @@ impl fmt::Display for Clock {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let hours = self.minutes / 60;
         let mins = self.minutes % 60;
-        write!(f, "{:02}:{:02}", hours, mins)
+        write!(f, "{hours:02}:{mins:02}")
     }
 }
 

exercises/practice/decimal/.meta/example.rs

@@ -159,12 +159,12 @@ impl fmt::Display for Decimal {
         // left-padded with zeroes
         let digits = format!("{:0>width$}", self.digits, width = self.decimal_index);
         if self.decimal_index == digits.len() {
-            write!(f, "0.{}", digits)
+            write!(f, "0.{digits}")
         } else if self.decimal_index == 0 {
-            write!(f, "{}", digits)
+            write!(f, "{digits}")
         } else {
             let (before_index, after_index) = digits.split_at(digits.len() - self.decimal_index);
-            write!(f, "{}.{}", before_index, after_index)
+            write!(f, "{before_index}.{after_index}")
         }
     }
 }

exercises/practice/dominoes/.meta/example.rs

@@ -50,7 +50,7 @@ impl AvailabilityTable {
             }
         } else {
             // For this toy code hard explicit fail is best
-            panic!("remove for 0 stones: ({:?}, {:?})", x, y)
+            panic!("remove for 0 stones: ({x:?}, {y:?})")
         }
     }
 

exercises/practice/grep/.meta/example.rs

@@ -88,7 +88,7 @@ pub fn grep(pattern: &str, flags: &Flags, files: &[&str]) -> Result<Vec<String>,
                     }
 
                     if is_multiple_file_search {
-                        result.insert_str(0, &format!("{}:", file_name))
+                        result.insert_str(0, &format!("{file_name}:"))
                     }
 
                     if flags.print_file_name {

exercises/practice/raindrops/.meta/example.rs

@@ -13,7 +13,7 @@ pub fn raindrops(n: u32) -> String {
         drops.push_str("Plong");
     }
     if drops.is_empty() {
-        let s = format!("{}", n);
+        let s = format!("{n}");
         drops.push_str(&s);
     }
     drops

exercises/practice/roman-numerals/.meta/example.rs

@@ -36,7 +36,7 @@ impl fmt::Display for Roman {
                 start -= numeric;
             }
         }
-        write!(f, "{}", result)
+        write!(f, "{result}")
     }
 }
 

exercises/practice/two-fer/.meta/example.rs

@@ -1,6 +1,6 @@
 pub fn twofer(name: &str) -> String {
     match name {
         "" => "One for you, one for me.".to_string(),
-        _ => format!("One for {}, one for me.", name),
+        _ => format!("One for {name}, one for me."),
     }
 }