doc: rephrase wording of child_process.execSync()

Rephrases the error thrown by child_process.execSync().

Fixes: nodejs#14944

doc/api/child_process.md

@@ -685,8 +685,8 @@ does not exit, the parent process will still wait until the child process has
 exited.
 
 If the process times out, or has a non-zero exit code, this method ***will***
-throw.  The [`Error`][] object will contain the entire result from
-[`child_process.spawnSync()`][]
+throw an [`Error`][] that will include the full result of the underlying
+[`spawnSync()`][].
 
 ### child_process.execSync(command[, options])
 <!-- YAML
@@ -1339,6 +1339,7 @@ unavailable.
 [`process.on('disconnect')`]: process.html#process_event_disconnect
 [`process.on('message')`]: process.html#process_event_message
 [`process.send()`]: process.html#process_process_send_message_sendhandle_options_callback
+[`spawnSync()`]: #child_process_child_process_spawnsync_command_args_options
 [`stdio`]: #child_process_options_stdio
 [`util.promisify()`]: util.html#util_util_promisify_original
 [Default Windows Shell]: #child_process_default_windows_shell