What?

This PR updates the .editorconfig file with additional properties indent_style and indent_size, with equivalent configuration as the .prettierrc file. Resolves #425

Why?

The EditorConfig file is often used by code editors to adjust configuration per project. For example, the VS Code extension editorconfig-vscode looks for an .editorconfig file in any open project and adjusts the behavior of the TAB key based on its configuration.

How?

Update the .editorconfig file.

Testing Instructions

1. Check out the branch.
2. Open one of the project files with a code editor that supports .editorconfig.
3. Press the TAB key to insert hard tab with width 4.