feat: export runtime error strings (vuejs#9301)

These strings are used for automatically generating error references in the documentation and should be considered internal. The code-to-string mapping is **not** part of the public API and can change between non-major versions.

They are also exposed only in dev or the esm-bundler builds.

packages/runtime-core/src/index.ts

@@ -140,6 +140,15 @@ export {
 } from './components/BaseTransition'
 export { initCustomFormatter } from './customFormatter'
 
+import { ErrorTypeStrings as _ErrorTypeStrings } from './errorHandling'
+/**
+ * Runtime error messages. Only exposed in dev or esm builds.
+ * @internal
+ */
+export const ErrorTypeStrings = (
+  __ESM_BUNDLER__ || __DEV__ ? _ErrorTypeStrings : null
+) as typeof _ErrorTypeStrings
+
 // For devtools
 export { devtools, setDevtoolsHook } from './devtools'