upd docs

docs/subpages.md

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+# Subpages
+
+You can configure entities with with the prefix `navigate`, that are navigating to cards, in case it's hidden card, the navigation items will change and the arrow is bringing you back to the privious page.
+
+```yaml
+          - entity: navigate.cardGrid_testKey
+```
+
+will allow you to navigate to a cardGrid page with the configured key testKey
+
+```yaml
+    hiddenCards:
+      - type: cardGrid
+        title: Exmaple Grid
+        entities:
+          - entity: light.test_item
+        key: testKey
+```