docs: add typescript template

[Zamiell]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "X" next to an item)

[X] Documentation update

What changes did you make? (Give an overview)

This is a follow-up on my last PR, #17423.

@nzakas mentioned in the ESLint Discord server that we should move forward with reducing the duplication introduced with my last PR by using a frontmatter template, which this PR includes.

Additionally, I also documented the remaining known ESLint core rules that conflict with the TypeScript compiler.

Additional Discussion

When doing this PR, I noticed that the rules pages have inconsistent formatting.
Rules randomly have either 1, 2, 3, or 5 newlines after the frontmatter.
This kind of thing makes it difficult for people to contribute, as it makes finding the proper style non-trivial.
I propose that docs should be formatted using Prettier (or dprint), in the same way that the @typescript-eslint project does.

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[AndreaPontrandolfo]

@Zamiell

Are you sure about no-redeclare?
From the docs:

In JavaScript, it’s possible to redeclare the same variable name using var.

Typescript seem to warn about re-declared let and const variables, but not var variables, which is precisely the usecase of this rule.

Also for no-import-assign Typescript doesn't seem to warn about this case:

Object.assign(mod_ns, { foo: "foo" })

while the ESLint rule does.

[Zamiell]

@AndreaPontrandolfo Thank you. I have verified your findings, so I will update the PR.

To clarify, I was using this as a reference: https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/eslint-plugin/src/configs/eslint-recommended.ts

I will also bring this up with the typeScript-eslint team.

[Zamiell]

The PR is updated now. (I also opened an issue at the typescript-eslint repository.)

[nzakas]

Nice! This LGTM. Would like someone to verify the compiler warnings for TypeScript.

(@JoshuaKGoldberg would you be able to do that?)

[Zamiell]

@AndreaPontrandolfo See Brad's reply here. Given this, I think it does make sense to update the language in this PR as well.

[AndreaPontrandolfo]

@AndreaPontrandolfo See Brad's reply here. Given this, I think it does make sense to update the language in this PR as well.

I saw it. I'm not 100% onboard with his reasoning on that, but i understand it.
Your re-wording sounds good to me, it informs the user of the difference between the TS check and ESLint rule, makes sense to me 👍

[JoshuaKGoldberg]

Layout changes look good to me! I do wonder if it'd be possible to automate it just a bit more so that no .md file includes the explicit "it's mostly useless, but for this one edge case" text? Maybe not worth it.

A few of the error messages don't match what I get in the TS playground for 5.2.2. Requesting changes on that?

[Zamiell]

I do wonder if it'd be possible to automate it just a bit more

Ok, I added an extra_typescript_info variable to the template in my latest commit.

[nzakas]

Overall this looks good. Cleaned up some of the language and left a note about Markdown processing.

[Zamiell]

I commited all of your suggestions, but now it looks like this:

Not sure what the correct solution is here, I'm new to Eleventy.

[nzakas]

Okay, we're getting closer. I think if you add | safe after | markdown that should work. So | markdown | safe altogether.

[Zamiell]

That worked:

I committed the fix now.

[nzakas]

LGTM. Would like @JoshuaKGoldberg to verify his changes before merging.

[JoshuaKGoldberg]

💯 fantastic!

[snitin315]

One minor suggestion & then LGTM.