Style guide for markdowns

1. Use h1 headers for compulsory README section headings, like # Data Availability Statements.
2. Use h2 for subheadings.
3. Put file names in bacticks, like master.do.
4. Type lists and enumerations in markdown. Avoid including any HTML code unless absolutely necessary.
5. References are unordered lists.
6. Check for typos in URLs: these will stop Svelte from recognizing that they are URLs.