doc: rephrase wording of child_process.execSync()
Rephrases the error thrown by child_process.execSync().
Fixes: https://github.com/nodejs/node/issues/14944
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
doc