Add documentation surrounding Sass support

[Timer]

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[bugzpodder]

Just tried it out, works great. I don't know enough to properly document the feature, but in js I just do
import 'path/to/my.scss'
and inside a scss file I just do
@import 'path/to/my.scss'
and for node_module imports:
@import '~package/other.css'

[Timer]

Glad to hear it works for you -- that's what we were going for! 😃 Something that should "just work".

[adamwright104]

This is working for me. followed the install and changed the app.css and index.css to be scss and no styles show

[bradfordlemley]

Specifically, adding-a-css-preprocessor-sass-less-etc section in User Guide should be updated.

Note: node-sass needs to be included separately in app's devDependencies (intentional, as requested by CRA.)

[mareksuscak]

This may have been resolved in d7bffca#diff-4e6ec56f74ee42069aac401a4fe448ad

EDIT: although there's one thing that's not documented properly - *.module.scss - it relates to both SCSS and CSS modules section of the doc (reference)

[Timer]

Feel free to send PR update, @mareksuscak!

[mareksuscak]

@Timer done and linked to this issue. Here's a preview.