This reverts commit b0a25d5b.

Follow up on: https://github.com/Microsoft/vscode-docs/pull/896

Removes the extended documentation for the html preview since this now lives in the vscode docs

fixes #22804

- Revert changes to id in Ext description. No lowering of name.
- Implement an equal function to check equality of extensions
- Use above function to check the equality with extension description

- In Extension description in Extension host
- In Extension enablement service
- Rename identifier to id in IExtension

fixes #20983

fixes #20703

* Add Type Definition Provider API

Adds a new API to support type definition providers and adds an initial type definition provider for TypeScript

* Fix comment

* Addressing comments

* Fixer menu option ordering

* Added simple test