[docs] Update Expo config references to "app config" (#22645)

# Why

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Please describe the motivation for this PR, and link to relevant GitHub
issues, forums posts, or feature requests.
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[docs] Update Expo config references to "app config" (#22645)

# Why

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Please describe the motivation for this PR, and link to relevant GitHub
issues, forums posts, or feature requests.
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During the initial audit done by Jon, it was brought that we should be
consistent when using **app config** to represet
**app.json**/**app.config.js** files.

Currently, in many places, Expo config is used instead of **app
config**.

# How

This PR updates all references of Expo config to app config.

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How did you build this feature or fix this bug and why?
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# Test Plan

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reproduce your test, especially if this PR does not include automated
tests! If possible, please also provide terminal output and/or
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Changes have been tested by running docs locally.

# Checklist

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Please check the appropriate items below if they apply to your diff.
This is required for changes to Expo modules.
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- [x] 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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Co-authored-by: Bartosz Kaszubowski <[email protected]>

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[docs] fix Terminal content layout shift, remove unused page imports (#22596)

[docs] Remove /home directory structure and make all directories top level (#22068)

[docs] Fix typo and page title issues, add icons to BoxLinks & more (#22048)

[docs] Add a guide on How to build a config plugin and an Expo module (#21024)

# Why

Closes ENG-6060

# How

This PR adds a "Create a module with a config plugin" to the Expo
Modules API doc

[docs] Add a guide on How to build a config plugin and an Expo module (#21024)

# Why

Closes ENG-6060

# How

This PR adds a "Create a module with a config plugin" to the Expo
Modules API docs

# Test Plan

N / A

# Checklist

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

- [x] 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 `expo prebuild` & EAS Build (eg:
updated a module plugin).

---------

Co-authored-by: Aman Mittal <[email protected]>

show more ...