svelte-kit sync before checks - closes #5779 (#6339)

Author: Rich-Harris

Diff for: .changeset/weak-feet-cheer.md

@@ -0,0 +1,5 @@
+---
+'create-svelte': patch
+---
+
+Add svelte-kit sync to check scripts in checkjs templates

Diff for: packages/create-svelte/shared/+checkjs/package.json

@@ -1,7 +1,7 @@
 {
 	"scripts": {
-		"check": "svelte-check --tsconfig ./jsconfig.json",
-		"check:watch": "svelte-check --tsconfig ./jsconfig.json --watch"
+		"check": "svelte-kit sync && svelte-check --tsconfig ./jsconfig.json",
+		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./jsconfig.json --watch"
 	},
 	"devDependencies": {
 		"typescript": "^4.7.4",