fix(ssr): sourcemap initModule

[FuPeiJiang]

Description

this is for debugging +server.js when running Run Script: dev
, currently, vscode finds the correct file, but when vscode stops at debugger; statement, the line number is off by +2.

this is because those two lines are always added:

(async function anonymous(global,__vite_ssr_exports__,__vite_ssr_import_meta__,__vite_ssr_import__,__vite_ssr_dynamic_import__,__vite_ssr_exportAll__
) {

I consider this eval() but it's new AsyncFunction

I assume initModule() is used for debugging only (vite dev), and not for prod (vite build then vite preview)
so my fix is to pad the sourcemap : mappings : with ;;

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[sapphi-red]

Closing as this is implemented by #11780