[Docs] Update design/multiprocessing.md

[windsonsea]

Perform a few cleanup actions for improvement:

• fix grammars
• put inline code and links in a single line

[chatgpt-codex-connector]

Codex usage limits have been reached for code reviews. Please check with the admins of this repo to increase the limits by adding credits.

[mergify]

Documentation preview: https://vllm--30677.org.readthedocs.build/en/30677/

[gemini-code-assist]

Code Review

This pull request introduces a series of improvements to the design/multiprocessing.md documentation. The changes focus on enhancing readability and correctness through grammatical fixes, rephrasing for clarity, and formatting adjustments. Specifically, list items have been made more concise, sentences have been reworded for better flow, and inline code blocks and links have been consolidated onto single lines. These modifications contribute to a cleaner and more professional document. The changes are well-executed and I have no further recommendations.