syntax: Improve --pretty normal slightly

When printing doc comments, always put a newline after them in a macro
invocation to ensure that a line-doc-comment doesn't consume remaining tokens on
the line.

src/librustc/util/ppaux.rs

@@ -360,17 +360,17 @@ pub fn ty_to_str(cx: &ctxt, typ: t) -> StrBuf {
       ty_uint(t) => ast_util::uint_ty_to_str(t, None,
                                              ast_util::AutoSuffix).to_strbuf(),
       ty_float(t) => ast_util::float_ty_to_str(t).to_strbuf(),
-      ty_box(typ) => "@".to_strbuf() + ty_to_str(cx, typ),
-      ty_uniq(typ) => "~".to_strbuf() + ty_to_str(cx, typ),
-      ty_ptr(ref tm) => "*".to_strbuf() + mt_to_str(cx, tm),
+      ty_box(typ) => format_strbuf!("@{}", ty_to_str(cx, typ)),
+      ty_uniq(typ) => format_strbuf!("~{}", ty_to_str(cx, typ)),
+      ty_ptr(ref tm) => format_strbuf!("*{}", mt_to_str(cx, tm)),
       ty_rptr(r, ref tm) => {
           let mut buf = region_ptr_to_str(cx, r);
           buf.push_str(mt_to_str(cx, tm).as_slice());
           buf
       }
       ty_tup(ref elems) => {
         let strs: Vec<StrBuf> = elems.iter().map(|elem| ty_to_str(cx, *elem)).collect();
-        ("(".to_strbuf() + strs.connect(",") + ")").to_strbuf()
+        format_strbuf!("({})", strs.connect(","))
       }
       ty_closure(ref f) => {
           closure_to_str(cx, *f)

src/libsyntax/print/pprust.rs

@@ -841,7 +841,13 @@ impl<'a> State<'a> {
         match *tt {
             ast::TTDelim(ref tts) => self.print_tts(tts.as_slice()),
             ast::TTTok(_, ref tk) => {
-                word(&mut self.s, parse::token::to_str(tk).as_slice())
+                try!(word(&mut self.s, parse::token::to_str(tk).as_slice()));
+                match *tk {
+                    parse::token::DOC_COMMENT(..) => {
+                        hardbreak(&mut self.s)
+                    }
+                    _ => Ok(())
+                }
             }
             ast::TTSeq(_, ref tts, ref sep, zerok) => {
                 try!(word(&mut self.s, "$("));
@@ -2238,7 +2244,7 @@ impl<'a> State<'a> {
             ast::LitUint(u, t) => {
                 word(&mut self.s,
                      ast_util::uint_ty_to_str(t, Some(u),
-                                              ast_util::AutoSuffix).as_slice())
+                                              ast_util::ForceSuffix).as_slice())
             }
             ast::LitIntUnsuffixed(i) => {
                 word(&mut self.s, format!("{}", i))