Document strict route names

Closes #859

Author: bakerkretzmar

README.md

@@ -287,6 +287,20 @@ If you don't have Ziggy's NPM package installed, add the following to your `jsco
 }
 ```
 
+#### Strict route name type checking
+
+By default, even when you generate type definitions to enable better autocompletion, Ziggy still allows passing any string to `route()`. You can optionally enable strict type checking of route names, so that calling `route()` with a route name Ziggy doensn't recognizes triggers a type error. To do so, extend Ziggy's `TypeConfig` interface and set `strictRouteNames` to `true`:
+
+```ts
+declare module 'ziggy-js' {
+  interface TypeConfig {
+    strictRouteNames: true
+  }
+}
+```
+
+Place this declaration in a `.d.ts` type definition file somewhere in your project. Depending on your setup, you may need to add an `export {};` statement to the end of file so TypeScript can pick it up.
+
 ## JavaScript frameworks
 
 > [!NOTE]