Update Markdown to recommended best practices

[chartgerink]

This PR adjusts some of the markdown practices according to the recommended best practices.

Specifically:

• Adjust the heading levels to have one Header1 (title; # Header1) and rest be at least Heading2.
• Format italic as *italic* instead of _italic
• Format bold as **bold** instead of __bold__

I saw this while reading through the report - I fully understand this is pedantic and I have zero expectation for this to be merged if this is unhelpful. I figured I'd make this PR for the off case it would be helpful 😊

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (fb004c9) 70.83% compared to head (68656ae) 73.07%.
Report is 8 commits behind head on main.

❗ Current head 68656ae differs from pull request most recent head 67568ac. Consider uploading reports for the commit 67568ac to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #126      +/-   ##
==========================================
+ Coverage   70.83%   73.07%   +2.24%     
==========================================
  Files           4        4              
  Lines          24       26       +2     
==========================================
+ Hits           17       19       +2     
  Misses          7        7              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.