style: reword ast::print docs

Also, small formatting fix and removal of debugging test.

Author: BurntSushi

regex-syntax/src/ast/print.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 /*!
-This module provides a regular expression printer.
+This module provides a regular expression printer for `Ast`.
 */
 
 use std::fmt;
@@ -422,7 +422,7 @@ mod tests {
     }
 
     fn roundtrip_with<F>(mut f: F, given: &str)
-        where F: FnMut(&mut ParserBuilder) -> &mut ParserBuilder
+    where F: FnMut(&mut ParserBuilder) -> &mut ParserBuilder
     {
         let mut builder = ParserBuilder::new();
         f(&mut builder);
@@ -434,11 +434,6 @@ mod tests {
         assert_eq!(given, dst);
     }
 
-    #[test]
-    fn scratch() {
-        roundtrip(".");
-    }
-
     #[test]
     fn print_literal() {
         roundtrip("a");