Light fixes (#2455)

* Add optional commas for items in lists and tables

* A couple last fixes

tests/shell/pipeline/commands/internal.rs

@@ -454,6 +454,18 @@ fn list_with_commas() {
     assert_eq!(actual.out, "6");
 }
 
+#[test]
+fn it_expansion_of_tables() {
+    let actual = nu!(
+        cwd: ".",
+        r#"
+        echo foo | echo [[`foo {{$it}} bar`]; [`{{$it}} foo`]] | get "foo foo bar"
+        "#
+    );
+
+    assert_eq!(actual.out, "foo foo");
+}
+
 #[test]
 fn table_with_commas() {
     let actual = nu!(