docs: improve clarity and fix typos in type narrowing guide

[BHUVANSH855]

Description

This PR improves clarity and fixes minor issues in the type narrowing guide.

Changes

• Simplified wording for better readability
• Replaced "understand" with "recognize" for improved terminology
• Fixed typo ("dicussed" → "discussed")
• Fixed grammar issue ("function" → "functions")
• Minor formatting improvement to avoid unintended line breaks

Motivation

These changes make the documentation clearer, more consistent, and easier to understand, especially for new readers.

Notes

No functional changes; documentation-only update.

[BHUVANSH855]

Hi @JelleZijlstra, @srittau

Just checking in regarding the latest updates to this PR.
Kindly let me know if any further changes are required.

Thank you!

[davidhalter]

Since you keep working on this I'll say this:

I generally avoid interacting with LLM generated PRs , since they tend to strain maintainer resources. This PR feels very much like it was written by an LLM. I quickly checked the other parts and I don't think they are necessarily an upgrade, so maybe just remove those and only fix the grammar errors? I'm happy to merge those.

[BHUVANSH855]

Since you keep working on this I'll say this:

I generally avoid interacting with LLM generated PRs , since they tend to strain maintainer resources. This PR feels very much like it was written by an LLM. I quickly checked the other parts and I don't think they are necessarily an upgrade, so maybe just remove those and only fix the grammar errors? I'm happy to merge those.

Thanks for the feedback @davidhalter
I've reverted the broader wording changes, kept only the typo and grammar fixes, and squashed the commits into a single commit to keep the history clean.

[davidhalter]

Thanks!