[docs] expo update: strings.xml diff block (#22953)

# Why

Put strings.xml in a Diff block, followup from
https://github.com/expo/expo/pull/22883/files#r1230532588

# Test Plan

- [ ] manuall

[docs] expo update: strings.xml diff block (#22953)

# Why

Put strings.xml in a Diff block, followup from
https://github.com/expo/expo/pull/22883/files#r1230532588

# Test Plan

- [ ] manually checked amended pages

# Checklist

<!--
Please check the appropriate items below if they apply to your diff.
This is required for changes to Expo modules.
-->

- [ ] Documentation is up to date to reflect these changes (eg:
https://docs.expo.dev and README.md).
- [ ] Conforms with the [Documentation Writing Style
Guide](https://github.com/expo/expo/blob/main/guides/Expo%20Documentation%20Writing%20Style%20Guide.md)
- [ ] This diff will work correctly for `npx expo prebuild` & EAS Build
(eg: updated a module plugin).

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