Feature request: Expose API to get the width and height of the text editors

[xiyaowong]

API to get width and height of:

1. panels
2. windows
3. editors

Details

My current use case is the extension vscode-neovim. This extension integrates neovim into vscode to obtain a good vim mode experience. The basic mode of the extension is to synchronize highlight, text, cursor and other data in two directions. However, due to the lack of viewport APIs in vscode, the size of the viewport is currently hard-coded, and it is also difficult to achieve viewport scrolling synchronization.

Before this, someone filed a similar feature request #195406, but it was closed due to lack of votes. Hope this feature will be considered again.