update tests

Author: Rich-Harris

packages/svelte/tests/compiler-errors/samples/export-derived-state/_config.js

@@ -3,7 +3,8 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'invalid-derived-export',
-		message: 'Cannot export derived state from a module',
+		message:
+			'Cannot export derived state from a module. To expose the current derived value, export a function returning its value',
 		position: [24, 66]
 	}
 });

packages/svelte/tests/compiler-errors/samples/export-state/_config.js

@@ -3,7 +3,8 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'invalid-state-export',
-		message: 'Cannot export state from a module if it is reassigned',
+		message:
+			"Cannot export state from a module if it is reassigned. Either export a function returning the state value or only mutate the state value's properties",
 		position: [46, 86]
 	}
 });

packages/svelte/tests/compiler-errors/samples/runes-export-named-state/_config.js

@@ -3,7 +3,8 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'invalid-state-export',
-		message: 'Cannot export state from a module if it is reassigned',
+		message:
+			"Cannot export state from a module if it is reassigned. Either export a function returning the state value or only mutate the state value's properties",
 		position: [28, 53]
 	}
 });