wipman extension for VSCode

Extension development

Install project dependencies:
```
npm install  # do not use `npm ci`
```
Debug the extension in VSCode:
1. Run TypeScript compiler: npm run watch.
2. Open src/extension.ts in your editor.
3. Press F5.
4. Once the new VSCode instance is launched, select the Markdown language.
Publish extension:
1. Manually bump version:
```
npm version patch  # major/minor/patch/...
                   # see `npm version --help` for more options
```
  Check published versions if you are unsure about whether you need to bump the version or not.
2. Push latest changes: git push
3. Go to CI and manually approve to publish.
(AVOID WHEN POSSIBLE, use CI instead) Manually publish the extension:
1. Set up credentials as environment variables:
  - VSCODE_PUBLISHER_ID: publisher ID, see [here][1] for more context.
  - VSCE_PAT: personal access token, follow [these instructions][1] to get one.
2. Publish the extension bumping the version:
```
npm run publish minor  # major/minor/patch/...
                       # see `npm version --help` for more options
```
This will compile the extension with typescript (same as npm run vscode:prepublish) and upload it to the extension marketplace.

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