don't unnecessarily walk more in visitor and add more tests

tests/ui/redundant_closure_call_fixable.fixed

@@ -78,4 +78,11 @@ fn issue9956() {
         || || || 42
     }
     let _ = x()()()();
+
+    fn bar() -> fn(i32, i32) {
+        foo
+    }
+    fn foo(_: i32, _: i32) {}
+    bar()(42, 5);
+    foo(42, 5);
 }

tests/ui/redundant_closure_call_fixable.rs

@@ -78,4 +78,11 @@ fn issue9956() {
         || || || 42
     }
     let _ = x()()()();
+
+    fn bar() -> fn(i32, i32) {
+        foo
+    }
+    fn foo(_: i32, _: i32) {}
+    bar()((|| || 42)()(), 5);
+    foo((|| || 42)()(), 5);
 }

tests/ui/redundant_closure_call_fixable.stderr

@@ -110,5 +110,17 @@ error: try not to call a closure in the expression where it is declared
 LL |     let a = (|| echo!((|| 123)))()();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: try doing something like: `123`
 
-error: aborting due to 12 previous errors
+error: try not to call a closure in the expression where it is declared
+  --> $DIR/redundant_closure_call_fixable.rs:86:11
+   |
+LL |     bar()((|| || 42)()(), 5);
+   |           ^^^^^^^^^^^^^^ help: try doing something like: `42`
+
+error: try not to call a closure in the expression where it is declared
+  --> $DIR/redundant_closure_call_fixable.rs:87:9
+   |
+LL |     foo((|| || 42)()(), 5);
+   |         ^^^^^^^^^^^^^^ help: try doing something like: `42`
+
+error: aborting due to 14 previous errors