Ensure code format (#2138)

* chore: add missing Vue support for Vercel builds

* refactor: move some functions and module-level state into classes as private methods and properties to start to encapsulate Docsify

Also some small tweaks:

- move initGlobalAPI out of Docsify.js to start to encapsulate Docsify
- move ajax to utils folder
- fix some type definitions and improve content in some JSDoc comments
- use concise class field syntax
- consolidate duplicate docsify-ignore comment removal code

This handles a task in [Simplify and modernize Docsify](https://github.com/docsifyjs/docsify/issues/2104), as well as works towards [Encapsulating Docsify](https://github.com/docsifyjs/docsify/issues/2135).

* chore: add prettier code format check to our lint script, and add a prettier script for manually formatting the whole code base

* chore: update issue/pr templates

* chore: apply our format to the whole code base


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Co-authored-by: Koy <koy@ko8e24.top>
Co-authored-by: i544693 <369491420@qq.com>