This reverts commit e2c5ff9d.

Fixes #122602

- Add snippet
- Use markdown string for strings that use backticks
- Add enum descriptions for `supported`
- Mark `supported` as being required

Fixes #122605

This reverts commit 06694a8e, reversing
changes made to 36fe8423.

- Use markdown
- Use link

Fixes https://github.com/microsoft/vscode/issues/118267

Now enabled by default

Fixes #122579

Add missing padding-bottom for notebook markdown cells

Diff: https://github.com/xtermjs/xterm.js/compare/eedc314...4a7bbe6

Fixes #121017

Fixes https://github.com/microsoft/vscode/issues/119675

Rewriting how we do replacements in the webviewPreloads function to hopefully handle optimization better

For https://github.com/microsoft/vscode/issues/119110
Refs https://github.com/microsoft/vsmarketplace/issues/68#issuecomment-828635629