fix: Avoid using lsof -Q which is only available from lsof 4.95.0

[erikmd]

(Debian 11 (oldstable) and Ubuntu 22.04 LTS both have lsof 4.93.2.)

The only drawback we could expect is generating a nonzero exit code, but the current implementation with Unix.open_process_in works as is.

• Kind: bugfix

• Close Bug: learn-ocaml master can raise lsof: illegal option character: Q #580

Description

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