Converted println braces to more conventional parentheses

Author: MCluck90

src/conversion/string.md

@@ -42,7 +42,7 @@ fn main() {
     let turbo_parsed = "10".parse::<i32>().unwrap();
 
     let sum = parsed + turbo_parsed;
-    println!{"Sum: {:?}", sum};
+    println!("Sum: {:?}", sum);
 }
 ```