[docs] Add docs on composing `css` with `styled`

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Steps to reproduce 🕹

Link to live example:
https://codesandbox.io/s/sweet-meitner-1c6fev?file=/src/App.tsx

No steps to reproduce, just open the link above and you'll see the problem.

Current behavior 😯

Error: styleArg.raw is undefined

Expected behavior 🤔

If I understand the emotion documentation on this correctly, it would expect an array when composing two or more sets of styles. So expected behaviour, I guess, is "it just works".

However, even if this is not correct, I feel documentation on how to actually use css & styled when imported from MUI, is kind of... Missing? Or am I overlooking it?

Context 🔦

It's probably also worth nothing that a styled component created this way, doesn't even have to be used anywhere in order for this error to show up. It breaks at the point of declaring the component, not at the point of using it somewhere. That's probably why the stack trace is quite short.

Your environment 🌎

System:
    OS: Windows 10 10.0.19045
  Binaries:
    Node: 18.15.0 - C:\Program Files\nodejs\node.EXE
    Yarn: Not Found
    npm: 9.6.7 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 113.0.5672.127
    Edge: Spartan (44.19041.1266.0), Chromium (113.0.1774.50)
  npmPackages:
    @emotion/react:  11.10.6
    @emotion/styled:  11.10.6
    @mui/base:  5.0.0-alpha.124
    @mui/core-downloads-tracker:  5.11.16
    @mui/material:  5.11.16
    @mui/private-theming:  5.12.0
    @mui/styled-engine:  5.11.16
    @mui/styles:  5.12.0
    @mui/system:  5.11.16
    @mui/types:  7.2.4
    @mui/utils:  5.12.0
    @types/react:  18.2.0
    react:  18.2.0
    react-dom:  18.2.0
    typescript:  4.9.5

For the sake of completeness, I'm on Firefox 113, but I really don't think it matters much.

Start with the linked CodeSandbox and review the MUI documentation for the imported css and styled APIs, alongside the referenced Emotion composition guidance. Document the supported way to compose multiple style sets and clarify the expected behavior for the reported styleArg.raw error.