## Summary of the Pull Request
Updates the `closeTab` action to optionally take an index.
## PR Checklist
* [x] Closes#7180
* [x] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [ ] Tests added/passed
* [x] Documentation updated. If checked, please file a pull request on [our docs repo](https://github.com/MicrosoftDocs/terminal) and link it here: MicrosoftDocs/terminal#347
* [x] Schema updated.
* [ ] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx
## Validation Steps Performed
Added the following configuration to `settings.json` and validated both key combinations behaved as expected. Also opened the command palette and ensured that the actions were displayed.
```json
{ "command": "closeTab", "keys": "ctrl+shift+delete" },
{ "command": { "action": "closeTab", "index": 0 }, "keys": "ctrl+shift+end" }
```
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