docs: fix typos in os API reference

[Ankit-Mohanty-23]

Found two typos in docs/api/os.md:

1. stardard → standard in updateSpawnedProcess parameter description
2. Accpeted → Accepted appears 3 times — in showNotification
   and showMessageBox (twice)

I'd like to fix these in a single PR.

[Ankit-Mohanty-23]

There are now two PRs for this issue.
The Original PR was submitted 3 days before the duplicate
Original PR: #455

Flagging for maintainer attention.