Add a note about interfaces in typescript section

Author: satya164

versioned_docs/version-6.x/typescript.md

@@ -52,6 +52,8 @@ And then we can use it:
 
 This will provide type checking and intelliSense for props of the `Navigator` and `Screen` components.
 
+> Note: The type containing the mappings must be a type alias (e.g. `type RootStackParamList = { ... }`). It cannot be an interface (e.g. `interface RootStackParamList { ... }`). It also shouldn't extend `ParamListBase` (e.g. `interface RootStackParamList extends ParamListBase { ... }`). Doing so will result in incorrect type checking where it allows you to pass incorrect route names.
+
 ### Type checking screens
 
 To type check our screens, we need to annotate the `navigation` prop and the `route` prop received by a screen. The navigator packages in React Navigation export a generic types to define types for both the `navigation` and `route` props from the corresponding navigator.