[sx] support function declaration

[siriwatknp]

Summary

A framework like Next.js transpile the code from ArrowFunction to FunctionDeclaration that developers don't have control:

 ⨯ unhandledRejection: SyntaxError: /Users/siriwatknp/practice-repos/nextjs-tailwind-v4/src/app/landing-page/components/Features.tsx: @pigment-css/react: sx prop only supports arrow functions directly returning an object, for example () => ({color: 'red'}). You can accept theme object in the params if required.
  171 |                             children: [
  172 |                                 /*#__PURE__*/ _jsxDEV(Box, {
> 173 |                                     sx: (param)=>{
      |                                                  ^
  174 |                                         let { theme } = param;
  175 |                                         return {
  176 |                                             backgroundSize: "cover",

The original code is:

<Box
  sx={({ theme }) => ({
    backgroundSize: 'cover',
    backgroundPosition: 'center',
    minHeight: 280,
    backgroundImage: 'var(--Image-light)',
    ...theme.applyStyles('dark', {
       backgroundImage: 'var(--Image-dark)',
    }),
  })}

The sx prop should work with function declaration too.

Examples

No response

Motivation

No response

Search keywords: sx function declaration

[siriwatknp]

I don't think we need this since #50