Indentation of template for custom extractor test is wrong

[svenwiegand]

• Platform: Visual Studio Code
• Mercury Parser Version: master
• Node Version (if a Node bug): v11.1.0
• Browser Version (if a browser bug): n/a

Expected Behavior

Wenn creating the template for a new custom extractor I expect the index.test.js to have correct indentation.

Current Behavior

Instead indentation is mixed.

Steps to Reproduce

Create a new custom extractor using yarn generate-parser.

Possible Solution

Fix template (wherever it might be located)