[docs] Encourage mui-rff

[lookfirst]

link the form libraries. shorter and more consistent description text.

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

[mui-pr-bot]

No bundle size changes comparing b841933...8869ced

Generated by 🚫 dangerJS against 8869ced

[oliviertassinari]

Thanks for pushing the final form integration further :)

[lookfirst]

Looks like the test failures are unrelated.

.................................12 02 2020 19:21:12.003:ERROR [launcher.browserstack]: Can not start Chrome 49.0 (OS X Sierra)
  Error: Validation Failed - `device` required
12 02 2020 19:21:12.011:ERROR [launcher.browserstack]: Can not start Edge 14.0 (Windows 10)
  Error: Validation Failed - `device` required
................................12 02 2020 19:21:12.064:ERROR [launcher.browserstack]: Can not start Firefox 52.0 (Windows 10)
  Error: Validation Failed - `device` required

[lookfirst]

@oliviertassinari It would be nice to somehow promote these utilities in places other than just at the bottom of a single form component page. Copy/paste to the other form components feels weird.

The lack of a single page with a demo of many form components has also identified some weirdness in how they interact together (like defaulting to the non-default margin="normal" to get proper spacing).

Also, most of my traffic is from the MUI site, so getting more eyes would be nice. Suggestions?

[oliviertassinari]

We have forgotten about /docs/src/pages/components/text-fields/text-fields.md

[lookfirst]

Forgotten?

[oliviertassinari]

Oops, my bad, it was the related projects that was forgotten, fixed, thanks :)