syntax: ViewItemUse no longer contains multiple view paths.

it reflected the obsolete syntax `use a, b, c;` and did not make
past the parser (though it was a non-fatal error so we can continue).
this legacy affected many portions of rustc and rustdoc as well,
so this commit cleans them up altogether.

src/librustdoc/html/render.rs

@@ -1165,12 +1165,10 @@ fn item_module(w: &mut Writer, cx: &Context,
                         try!(write!(w, ";</code></td></tr>"));
                     }
 
-                    clean::Import(ref imports) => {
-                        for import in imports.iter() {
-                            try!(write!(w, "<tr><td><code>{}{}</code></td></tr>",
-                                          VisSpace(myitem.visibility),
-                                          *import));
-                        }
+                    clean::Import(ref import) => {
+                        try!(write!(w, "<tr><td><code>{}{}</code></td></tr>",
+                                      VisSpace(myitem.visibility),
+                                      *import));
                     }
                 }