Winter is coming theme is either overriding or not specifying default markup textMateRules

[smcenlly]

Describe the bug Winter is coming theme is either overriding or not specifying default markup textMateRules that are provided with VS Code default themes. This breaks syntax highlighting in extensions that use these rules.

To Reproduce Steps to reproduce the behavior:

1. Clone https://github.com/smcenlly/missing-textmate-tokens VS Code sample extension.
2. Open the repo and run npm install
3. Open the repo in VS Code and Start debugging (F5).
4. Create a new file (Ctrl + N).
5. Change its language to markup using the Change Language Mode command
6. Paste the contents below:

deleted

inserted

underline

7. Using any of the VS Code themes, you will see output similar to:

Expected behavior Winter is coming should provide similar formatting (adjusted to its themes). Instead, no highlighting is displayed.

[smcenlly]

Bumping this issue - any plans to fix?