message: Add mac/linux quickstart to Contributing.md
diff: # Contributing to LaTeX-Workshop
  +## Quickstart (mac/linux)
  +
  +```bash
  +git clone https://github.com/James-Yu/LaTeX-Workshop.git
  +cd ./LaTeX-Workshop
  +npm install --no-optional
  +command code .
  +```
  +Press <kbd>F5</kbd> in vscode to start the development version in debug mode.
  +
  ## Prerequisites for building the extension
  Make sure you have installed:
  @@ -30,7 +40,7 @@ To build a release image, run
  ## Testing and debugging the extension
  -In VS Code, simply press `<F5>` (or run `Debug: Start Debugging` from the command palette) and a new window will pop up where you can test the extension.
  +In VS Code, simply press <kbd>F5</kbd> (or run `Debug: Start Debugging` from the command palette) and a new window will pop up where you can test the extension.
  ### Debugging PDF viewer
  