Fix some typos in comment

Diff: https://github.com/xtermjs/xterm.js/compare/cdc9f79...846a189

- Saved absolute cursor position (xtermjs/xterm.js#2217)
- Buffer line refactor (moving parts into new files)
- Splitting Types.ts into .d.ts and Constants.ts
- Fix refresh after DPR change
- Fix NPE in setTheme (didn't affect VS Codee)

Fixes #75575
Fixes #75576

## Problem
We use a custom `vscode-resource` protocol to control access to local resources inside of webviews. This will not work on the web, but we still would prefer a way to intercept webview requests from the main client

## Proposed solution
Move webviews into their own origin and register a service worker on this origin. This service worker can talk with the outer iframe of our webview. When a request for a resource comes in to the service worker:

* In the service worker, add the request to a map and post a message back to the client saying we want to load this resource
* The outer iframe gets the message from the sercice worker and forwards it to our main process
* This process handles the message and use the normal file system api to read the resource (also restricting which files can be read)
* We post the result back into the inner iframe which fowards it back to the service worker
* The service worker now resolves the pending request.

The prototype version in this change works but does not correctly handle multiple clients existing at the same time (plus probably a lot of other edge cases too)

Iframe based webview prototype

* add window.disableMenuBarAltBehavior option

* enable alt behavior when menuBarVisibility is set to 'toggle'

* rename 'window.disableMenuBarAltBehavior' to 'window.disableCustomMenuBarAltBehavior' and change its description

* don't affect mnemonics

Diff https://github.com/xtermjs/xterm.js/compare/566f594...cdc9f79

- Addon webpacking
- Docs
- Fix DOM cursor blink
- Remove some IE workarounds

Fixes #75534

Terminal race between process exit and on ready listeners

Mark events as readonly in VS Code api

Fixes #75509

Fix LANG env var for Czech