fix(types): fix incorrect LuaLS types

[lucario387]

Without the added parentheses, the type were resolved to

(field) keys: (
  |string
  |LazyKeysSpec[]
  |fun(self: LazyPlugin, keys: string[]):string
  |LazyKeys[]
  |string[]
)?

With the paren, it now correctly resolves to

(field) keys: (
  |string
  |LazyKeysSpec[]
  |fun(_: LazyPlugin, keys: string[]):(string|LazyKeys)[]
  |string[]
)?

[folke]

thanks!