feat(module): improve app config types autocomplete (#1870)

Co-authored-by: Dave Stewart <dev@davestewart.co.uk>
Co-authored-by: Benjamin Canac <canacb1@gmail.com>

src/module.ts

@@ -21,7 +21,7 @@ type UI = {
   colors?: string[]
   strategy?: Strategy
   [key: string]: any
-} & DeepPartial<typeof config>
+} & DeepPartial<typeof config, string>
 
 declare module 'nuxt/schema' {
   interface AppConfigInput {