Rhombus is unusable in `racket/sandbox`.

[eutro]

Attempting to use rhombus within racket/sandbox currently triggers an error about something in (submod rhombus/private/amalgam demod-pane-1) being disallowed by the code inspector.

Welcome to Racket v8.16 [cs].
> (require racket/sandbox)
> (make-evaluator 'rhombus)
?: access disallowed by code inspector to unexported transformer
  from module: (submod "/home/eutro/.local/share/racket/8.16/pkgs/rhombus-lib/rhombus/private/amalgam.rkt" demod-pane-1)
  at: #%module-begin
  in: rhombus-module-begin
 [,bt for context]
> (define ev (make-evaluator 'racket))
> (ev "(require rhombus)")
> (ev "1")
?: access disallowed by code inspector to unexported transformer
  from module: (submod "/home/eutro/.local/share/racket/8.16/pkgs/rhombus-lib/rhombus/private/amalgam.rkt" demod-pane-1)
  at: #%top-interaction
 [,bt for context]

[mflatt]

The note in #656 probably should have gone here.

[mflatt]

Fixed in v8.17.