doc: improve child process synchronous API docs

[evanshortiss]

📗 API Reference Docs Problem

• Version: 14+

• Platform: N/A

• Subsystem: Child Process

Location

Section of the site where the content exists

Affected URL(s):

• https://nodejs.org/dist/latest-v16.x/docs/api/child_process.html#child_process_child_process_execfilesync_file_args_options
• https://nodejs.org/dist/latest-v16.x/docs/api/child_process.html#child_process_child_process_execsync_command_options
• https://nodejs.org/dist/latest-v16.x/docs/api/child_process.html#child_process_child_process_spawnsync_command_args_options

Description

Concise explanation of the problem

I'd like to suggest the following improvements to synchronous child process docs:

• The options.stdio argument should provide a link to the docs for that option (this is under the async spawn doc)
• Basic usage example(s)
• Exception handling example to demonstrate:
  • That stderr and stdio are attached to the error raised if a child exits with a none-zero code
  • That stderr and stdio are not attached to the error if options.stdio is set to ignore etc.

---

• I would like to work on this issue and
  submit a pull request.

[gireeshpunathil]

@evanshortiss - thanks, looks good to me! go ahead with your plan on a PR!

[evanshortiss]

@gireeshpunathil thank you! Will aim to get something drafted within 2 weeks.