n-api: fix comment on expected N-API version

Remove the comment about the expected version so
that it does not get out of sync. The code shows
the expected version anyway.

Signed-off-by: Michael Dawson <michael_dawson@ca.ibm.com>

PR-URL: https://github.com/nodejs/node/pull/32236


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>