Fix rustc complaining about indentation.

src/scanner.rs

@@ -318,6 +318,7 @@ struct Indent {
 /// consume/push a character. As of now, almost all lookaheads are 4 characters maximum, except:
 ///   - Escape sequences parsing: some escape codes are 8 characters
 ///   - Scanning indent in scalars: this looks ahead `indent + 2` characters
+///
 /// This constant must be set to at least 8. When scanning indent in scalars, the lookahead is done
 /// in a single call if and only if the indent is `BUFFER_LEN - 2` or less. If the indent is higher
 /// than that, the code will fall back to a loop of lookaheads.