fix: always a single leading space

src/formatting.rs

@@ -20,8 +20,8 @@ pub fn pretty_eval(mut input: String) -> Result<String, Error> {
     let significant_digits = get_significant_digits(&result);
 
     Ok(format!(
-        "{:leading_spaces$}{}{result:.significant_digits$}{}",
+        "{}{}{result:.significant_digits$}{}",
-        ' ',
+        " ".repeat(leading_spaces),
         if should_add_back_equals && should_add_back_alignment {
             "& = "
         } else if should_add_back_equals {