docs: add an empty validation doc and its navigation

docs/en/UI/Angular/Form-Validation.md

@@ -0,0 +1,5 @@
+# Form Validation
+
+## What's Next?
+
+- [Settings](./Settings.md)

docs/en/UI/Angular/Localization.md

@@ -237,4 +237,4 @@ import(
 
 ## What's Next?
 
-* [Settings](./Settings.md)
+* [Form Validation](./Form-Validation.md)

docs/en/docs-nav.json

@@ -628,6 +628,10 @@
                   "text": "Localization",
                   "path": "UI/Angular/Localization.md"
                 },
+                {
+                  "text": "Form Validation",
+                  "path": "UI/Angular/Form-Validation.md"
+                },
                 {
                   "text": "Settings",
                   "path": "UI/Angular/Settings.md"