Fix standard auto-formatting issues

[guidezpl]

Describe the problem

I wanted to contribute but in editing a few files, I realized they were hand formatted.

Examples

• HTML
• YML
• 

Expected fix

Fix standard auto-formatted issues (no trailing spaces, ensure ending newlines, HTML indented properly)

On which platform(s) did you experience this issue?

macOS

Additional context

VS Code out of the box formatters

[parlough]

Yeah we eventually need to add some formatting tools and checks, particularly for HTML and Markdown, but I don't want to require contributors to have Node or another tool.

For now, if you're updating a file, feel free to keep the auto formatting changes in your PR if you're changing those files and it's easier to keep them.