added helpful links to lints that have wiki entries

src/returns.rs

@@ -60,7 +60,7 @@ impl ReturnPass {
     fn emit_return_lint(&mut self, cx: &Context, spans: (Span, Span)) {
         span_lint(cx, NEEDLESS_RETURN, spans.0, &format!(
             "unneeded return statement. Consider using `{}` \
-             without the trailing semicolon",
+             without the return and trailing semicolon",
             snippet(cx, spans.1, "..")))
     }