docs: add react-native usage guide (#558)

docs/config.json

@@ -76,6 +76,10 @@
             {
               "label": "UI Libraries",
               "to": "framework/react/guides/ui-libraries"
+            },
+            {
+              "label": "React Native",
+              "to": "framework/react/guides/react-native"
             }
           ]
         },

docs/framework/react/guides/react-native.md

@@ -0,0 +1,29 @@
+---
+id: react-native
+title: Usage with React Native
+---
+
+Tanstack Form is headless and it should support React Native out-of-the-box without needing any additional configuration.
+
+Here is an example:
+
+```tsx
+<form.Field
+  name="age"
+  validators={{
+    onChange: val => val < 13 ? "You must be 13 to make an account" : undefined
+  }}
+>
+  {field => (
+    <>
+      <Text>Age:</Text>
+      <TextInput value={field.state.value} onChangeText={handleChange} />
+      {
+        field.state.meta.errors
+          ? <Text>{field.state.meta.errors.join(', ')}</Text>
+          : null
+      }
+    </>
+  )}
+</form.Field>
+```