[material-ui][docs] Standardize all references to Material Design 3 (M3)

[samuelsycamore]

Raised in this comment thread: #40446 (comment)

(From https://developer.android.com/codelabs/jetpack-compose-theming#0)

This PR replaces mentions of "Material 3" and "MD3" with either "Material Design 3" or "M3."

Though "Material 3" might be considered an acceptable synonym, I think it's overly confusing in our context. (Are we talking about Material UI v3?). We should err on the side of clarifying that we're talking about Material Design most of the time; after first mention, I think M3 works well to maintain that clarity.

I removed the names of the components from the headers in the component demo docs because they just felt redundant. The search experience could be better, but that's something we should address with the design of the search results if we want to improve it.

I've also done some rewriting of the @mui/material-next docs to reflect the changes to the release schedule (since M3 is coming in v7, not v6).

[mui-bot]

Netlify deploy preview

• docs/data/joy/customization/theme-typography/theme-typography.md
• docs/data/material/components/badges/badges.md
• docs/data/material/components/button-group/button-group.md
• docs/data/material/components/buttons/buttons.md
• docs/data/material/components/chips/chips.md

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[samuelsycamore]

The @mui/material-next codebase uses "Material You" and "MD3" throughout—should we standardize these as well? (I don't like "Material You" personally, because it's a nightmare to try to have a spoken conversation about "Material UI's implementation of Material You." 🙃)

[DiegoAndai]

Thanks for tackling this @samuelsycamore 😊

Regarding "Material You" and "MD3" mentions in @mui/material-next, we should standardize them as well.

[danilo-leal]

Looks great to me! 🤙

[oliviertassinari]

Nice 👍