Loudly error for invalid `:global` placement

[dummdidumm]

Describe the bug

In https://discord.com/channels/457912077277855764/1325334674784129035 someone was confused by a certain syntax failing with a "unclosed comment" error. Turns out it's us no erroring on a wrong :global placement, which leads to subsequent wrong "comment this out" logic.

The solution is to throw a validation error here.

Reproduction

playground link

Logs

No response

System Info

irrelevant

Severity

annoyance