Translate the Vim9 script Godot files to legacy.
`<scriptcmd>` is not ported yet, so replace it with `<Cmd>` and `<SID>`.
If it's ported, `<scriptcmd>call s:` can be used instead.
Includes changes from:
vim-patch:0daafaa7d99e (was partial, but is now pretty much fully ported)
vim-patch:9712ff1288f9
Co-authored-by: Maxim Kim <habamax@gmail.com>
