Place DO NOT EDIT comment on top of generated fourslash tests

Author: jakebailey

internal/fourslash/_scripts/convertFourslash.mts

@@ -2116,7 +2116,9 @@ function generateGoTest(failingTests: Set<string>, test: GoTest, isServer: boole
         imports.push(`. "github.com/microsoft/typescript-go/internal/fourslash/tests/util"`);
     }
     imports.push(`"github.com/microsoft/typescript-go/internal/testutil"`);
-    const template = `package fourslash_test
+    const template = `// Code generated by convertFourslash.mts; DO NOT EDIT.
+
+package fourslash_test
 
 import (
 	"testing"

internal/fourslash/_scripts/makeManual.mts

@@ -63,7 +63,9 @@ function main() {
 
 function markAsManual(genFilePath: string, manualFilePath: string) {
     const content = fs.readFileSync(genFilePath, "utf-8");
-    const updatedContent = content.replace(/^\s*t\.Skip\(\)\s*$/m, "");
+    let updatedContent = content.replace(/^\s*t\.Skip\(\)\s*$/m, "");
+    // Remove the generated header comment
+    updatedContent = updatedContent.replace(/^\/\/ Code generated by convertFourslash\.mts; DO NOT EDIT\.\n\n/, "");
     fs.writeFileSync(manualFilePath, updatedContent, "utf-8");
     fs.rmSync(genFilePath);
 }