add more helpful error for calling a decl that exists in a module (#6752)

* add more helpful error for calling a decl that exists in a module

* accord to suggestions

* make error more helpful

crates/nu-command/tests/commands/use_.rs

@@ -183,3 +183,17 @@ fn use_export_env_combined() {
         assert_eq!(actual.out, "foo");
     })
 }
+
+#[test]
+fn use_module_creates_accurate_did_you_mean() {
+    let actual = nu!(
+    cwd: ".", pipeline(
+        r#"
+                module spam { export def foo [] { "foo" } }; use spam; foo
+            "#
+        )
+    );
+    assert!(actual.err.contains(
+        "command 'foo' was not found but it exists in module 'spam'; try using `spam foo`"
+    ));
+}