[docs] Fix Chakra UI theme scoping typo

[mj12albert]

Just fixing a small typo discovered when trying to repro #36910

Proof that it works: https://codesandbox.io/s/chakra-material-forked-qsbpog?file=/src/App.tsx

Closes #36910

[mui-bot]

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[oliviertassinari]

I'm a bit confused by the API:

    <ChakraProvider theme={chakraTheme} resetCSS>
      <MaterialThemeProvider theme={{ [THEME_ID]: materialTheme }}>

Since ChakraProvider and MaterialThemeProvider share the theme React context singleton, I think that most developers should expect { [THEME_ID]: materialTheme } to override chakraTheme. Did we consider this API instead?

    <ChakraProvider theme={chakraTheme} resetCSS>
      <MaterialThemeProvider theme={{ [THEME_ID]: materialTheme }} mergeParentTheme>

or

    <ChakraProvider theme={chakraTheme} resetCSS>
      <MaterialThemeProvider theme={materialTheme} themeId={THEME_ID}>

I think either would be clearer. 2. might be better than 1.

[siriwatknp]

@oliviertassinari Agree, (2) looks better and it should simplify the types. Will open an improvement.