Fix dogfood

Author: mcarton

src/misc_early.rs

@@ -134,7 +134,7 @@ impl EarlyLintPass for MiscEarly {
                                        expr.span,
                                        "Try not to call a closure in the expression where it is declared.",
                                        |db| {
-                                            if decl.inputs.len() == 0 {
+                                            if decl.inputs.is_empty() {
                                                 let hint = format!("{}", snippet(cx, block.span, ".."));
                                                 db.span_suggestion(expr.span, "Try doing something like: ", hint);
                                             }