Docs: Update wording in Block Editor Handbook to reflect that all examples now use JSX

[atachibana]

What?

PR #56121 removed the vanilla JS example pragrams and {% codetabs %} instances. However, references to these examples remain in the content body.

This PR removes and/or modifies them. It also addresses the PR #56121's forgetting to remove them.
cc: @ryanwelcher @juanmaguitar

Why?

How?

Testing Instructions

Testing Instructions for Keyboard

Screenshots or screencast

[github-actions]

Warning: Type of PR label mismatch

To merge this PR, it requires exactly 1 label indicating the type of PR. Other labels are optional and not being checked here.

• Type-related labels to choose from: [Type] Automated Testing, [Type] Breaking Change, [Type] Bug, [Type] Build Tooling, [Type] Code Quality, [Type] Copy, [Type] Developer Documentation, [Type] Enhancement, [Type] Experimental, [Type] Feature, [Type] New API, [Type] Task, [Type] Performance, [Type] Project Management, [Type] Regression, [Type] Security, [Type] WP Core Ticket, Backport from WordPress Core.
• Labels found: .

Read more about Type labels in Gutenberg. Don't worry if you don't have the required permissions to add labels; the PR reviewer should be able to help with the task.

[juanmaguitar]

LGTM! ✅
Thanks a lot @atachibana for this PR!

[t-hamano]

@atachibana Sorry for the late review. Could you please rebase this PR and resolve the conflict?

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: atachibana <atachibana@git.wordpress.org>
Co-authored-by: juanmaguitar <juanmaguitar@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[atachibana]

@t-hamano
Sorry for late response. It seems to be passed all checks at all.

[t-hamano]

@atachibana Thanks for the update!

[t-hamano]

In the end, this PR landed on minor wording corrections and the removal of unnecessary code tabs? If so, I would appreciate it if you could update the PR title to reflect the actual changes 🙏