embed: document the maximum file size supported
embed: document the maximum file size supported

Fixes #47627

Change-Id: Ia1edfb6249863ab055fab68a35666bc2bdf21dcb
Reviewed-on: https://go-review.googlesource.com/c/go/+/341689
Reviewed-by: Jay Conrod <f3fadaedc813344da5ec13b41e26596889cc5baa@google.com>
Trust: Michael Matloob <4562438b12c14e81a47550acde616ff328a909f8@golang.org>

cloudflare/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,CAFxX/go,nawawi/go,cloudflare/go,golang/go,nawawi/go,cloudflare/go,nawawi/go,cloudflare/go,golang/go,nawawi/go,CAFxX/go,golang/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,nawawi/go,nawawi/go,cloudflare/go,CAFxX/go,golang/go,golang/go,cloudflare/go,CAFxX/go,CAFxX/go,CAFxX/go,golang/go