Do not expose Parser::into_comments

Since the parser's API is too widely open, users can easily break the binary
search provided by `Comments::find`. One possibility could be to expose
`Parser::into_comments` sorting the comments first, but have
`Parser::parse_sql_with_comments` do wihtout. To be decided later.

Author: xitep

src/parser/mod.rs

@@ -546,7 +546,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Consumes this parser returning comments from the parsed token stream.
-    pub fn into_comments(self) -> comments::Comments {
+    fn into_comments(self) -> comments::Comments {
         let mut comments = comments::Comments::default();
         for t in self.tokens.into_iter() {
             match t.token {