[docs] Remove unused imports and declarations

[merceyz]

• I have followed (at least) the PR section of the contributing guide.

[mui-pr-bot]

No bundle size changes comparing d1df9a8...0297e71

Generated by 🚫 dangerJS against 0297e71

[oliviertassinari]

Nice, what methodology did you use to spot them?

[merceyz]

what methodology did you use to spot them?

@oliviertassinari Saw a few of them when looking at the docs, enabled compile errors on unused variables to spot them and removed them manually.

[oliviertassinari]

@merceyz Would it be possible to move this compilation option to our tsconfig.json?

[eps1lon]

@merceyz Would it be possible to move this compilation option to our tsconfig.json?

In docs/tsconfig only preferably. We need unused variables for the other type tests.

[merceyz]

Yes, however it is a nightmare to have on when developing as it gives you compile errors, so it should only be enabled in CI builds. TSLint has an option for it but it's deprecated.

I can add a check in #15438 that will report the error when transpiling, it would only work if the whole import statement was unused

[oliviertassinari]

I agree for the CI only change. Sebastian is right. We are only interested in the docs folder.

[merceyz]

I'll hopefully have a PR ready tomorrow

[merceyz]

@oliviertassinari @eps1lon PR ready, #15501