Update UG and DG site json file to include new plugins

[EltonGohJH]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• DevOps
• Improve developer experience
• Others, please explain:

Overview of changes:
Fixes #2451
Update UG and DG site json file to include new plugins

Anything you'd like to highlight/discuss:
I realised that these plugins are not enabled after looking at issue #2529 which is kinda ironic.

Testing instructions:
Merge to master to test. Quite confident this will solve it 😆

Proposed commit message: (wrap lines at 72 characters)
Update UG and DG site json file to include new plugins

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Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features
• Linked all related issues
• No unrelated changes

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Reviewer checklist:

Indicate the SEMVER impact of the PR:

• Major (when you make incompatible API changes)
• Minor (when you add functionality in a backward compatible manner)
• Patch (when you make backward compatible bug fixes)

At the end of the review, please label the PR with the appropriate label: r.Major, r.Minor, r.Patch.

Breaking change release note preparation (if applicable):

• To be included in the release note for any feature that is made obsolete/breaking

Give a brief explanation note about:

• what was the old feature that was made obsolete
• any replacement feature (if any), and
• how the author should modify his website to migrate from the old feature to the replacement feature (if possible).

[kaixin-hc]

lgtm lmao I wish we merged this earlier

[damithc]

I realised that these plugins are not enabled after looking at issue #2529 which is kinda ironic.

Good catch, @EltonGohJH

lgtm lmao I wish we merged this earlier

I guess we need to do another release? :-p

[EltonGohJH]

@damithc
I think @LamJiuFong wants to do more changes after finals.

@kaixin-hc is thinking of doing a release after that if there are any changes.

[damithc]

@kaixin-hc is thinking of doing a release after that if there are any changes.

It's best to fix the UG sooner rather than later though (as it is a public-facing), if not through a release, then by doing a manual update.

[tlylt]

@EltonGohJH does our DG use any of the added plugins? Especially the ones like web3Form? I believe that's the reason why some of these are not added to our DG.

In addition, I think it's fine that we don't include the newly included datatable or mermaid plugins if we don't use them. It should be a valid use case where users can opt to remove the plugins in the site.json file and MarkBind will still work? If so our docs will successfully illustrate that.

[EltonGohJH]

@tlylt
I added because I thought it should be consistent but on hindsight maybe I should have only enabled what is used. I agree that our DG can serve as use case for the behaviour for site.json.