doc: update spawnSync() status value possibilities

The object returned by `child_process.spawnSync()` can have the `status` property set to `null` if the process terminated due to a signal. We even test for this in test/parallel/test-child-process-spawnsync-kill-signal.js. Update the documentation to reflect this. PR-URL: #26680 Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Gireesh Punathil <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Sakthipriyan Vairamani <[email protected]>

Author: Trott

doc/api/child_process.md

@@ -860,8 +860,10 @@ changes:
 *`output`{Array} Array of results from stdio output.
 *`stdout`{Buffer|string} The contents of `output[1]`.
 *`stderr`{Buffer|string} The contents of `output[2]`.
-*`status`{number} The exit code of the child process.
-*`signal`{string} The signal used to kill the child process.
+*`status`{number|null} The exit code of the subprocess, or `null` if the
+ subprocess terminated due to a signal.
+*`signal`{string|null} The signal used to kill the subprocess, or `null` if
+ the subprocess did not terminate due to a signal.
 *`error`{Error} The error object if the child process failed or timed out.
 
 The `child_process.spawnSync()` method is generally identical to