enhance error message

packages/svelte/messages/compile-errors/script.md

@@ -162,4 +162,4 @@ Using a `$` prefix to refer to the value of a store is only possible inside `.sv
 
 ## typescript_invalid_feature
 
-> TypeScript language features like %feature% are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler
+> TypeScript language features like %feature% are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)

packages/svelte/src/compiler/errors.js

@@ -435,13 +435,13 @@ export function store_invalid_subscription_module(node) {
 }
 
 /**
- * TypeScript language features like %feature% are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler
+ * TypeScript language features like %feature% are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)
  * @param {null | number | NodeLike} node
  * @param {string} feature
  * @returns {never}
  */
 export function typescript_invalid_feature(node, feature) {
-	e(node, "typescript_invalid_feature", `TypeScript language features like ${feature} are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler`);
+	e(node, "typescript_invalid_feature", `TypeScript language features like ${feature} are not natively supported, and their use is generally discouraged. Outside of \`<script>\` tags, these features are not supported. For use within \`<script>\` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using \`vitePreprocess\`, make sure to specifically enable preprocessing script tags (\`vitePreprocess({ script: true })\`)`);
 }
 
 /**

packages/svelte/tests/validator/samples/ts-unsupported-accessor/errors.json

@@ -1,7 +1,7 @@
 [
 	{
 		"code": "typescript_invalid_feature",
-		"message": "TypeScript language features like accessor fields (related TSC proposal is not stage 4 yet) are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler",
+		"message": "TypeScript language features like accessor fields (related TSC proposal is not stage 4 yet) are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)",
 		"start": {
 			"line": 3,
 			"column": 2

packages/svelte/tests/validator/samples/ts-unsupported-decorator/errors.json

@@ -1,7 +1,7 @@
 [
 	{
 		"code": "typescript_invalid_feature",
-		"message": "TypeScript language features like decorators (related TSC proposal is not stage 4 yet) are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler",
+		"message": "TypeScript language features like decorators (related TSC proposal is not stage 4 yet) are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)",
 		"start": {
 			"line": 2,
 			"column": 4

packages/svelte/tests/validator/samples/ts-unsupported-enum/errors.json

@@ -1,7 +1,7 @@
 [
 	{
 		"code": "typescript_invalid_feature",
-		"message": "TypeScript language features like enums are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler",
+		"message": "TypeScript language features like enums are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)",
 		"start": {
 			"line": 2,
 			"column": 1

packages/svelte/tests/validator/samples/ts-unsupported-modifier/errors.json

@@ -1,7 +1,7 @@
 [
 	{
 		"code": "typescript_invalid_feature",
-		"message": "TypeScript language features like accessibility modifiers on constructor parameters are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler",
+		"message": "TypeScript language features like accessibility modifiers on constructor parameters are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)",
 		"start": {
 			"line": 3,
 			"column": 14

packages/svelte/tests/validator/samples/ts-unsupported-namespace/errors.json

@@ -1,7 +1,7 @@
 [
 	{
 		"code": "typescript_invalid_feature",
-		"message": "TypeScript language features like namespaces with non-type nodes are not natively supported, and their use is generally discouraged. You will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler",
+		"message": "TypeScript language features like namespaces with non-type nodes are not natively supported, and their use is generally discouraged. Outside of `<script>` tags, these features are not supported. For use within `<script>` tags, you will need to use a preprocessor to convert it to JavaScript before it gets passed to the Svelte compiler. If you are using `vitePreprocess`, make sure to specifically enable preprocessing script tags (`vitePreprocess({ script: true })`)",
 		"start": {
 			"line": 2,
 			"column": 1