[HOLD for payment 2023-10-25] Updates to the help site's visual design

[maddylewis]

Main cleanup tracking issue - #28497

Problem

The existing help site pages are challenging to read -- the text is close together, the headings aren't sized correctly, the background vs text color is creating readability issues.

• Example help page: International Reimbursements
• Slack convo: HERE

Solution(s)

1. Create more space between text
2. Create more space between paragraphs
3. Update how the # and ### headers are styled on the site
4. Alternate the backgrounds between headers to help visually separate the sections of the resource more

[melvin-bot]

Triggered auto assignment to @sakluger (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details.

[melvin-bot]

Triggered auto assignment to @dubielzyk-expensify (Design), see these Stack Overflow questions for more details.

[melvin-bot]

Bug0 Triage Checklist (Main S/O)

• This "bug" occurs on a supported platform (ensure Platforms in OP are ✅)
• This bug is not a duplicate report (check E/App issues and #expensify-bugs)
  • If it is, comment with a link to the original report, close the issue and add any novel details to the original issue instead
• This bug is reproducible using the reproduction steps in the OP. S/O
  • If the reproduction steps are clear and you're unable to reproduce the bug, check with the reporter and QA first, then close the issue.
  • If the reproduction steps aren't clear and you determine the correct steps, please update the OP.
• This issue is filled out as thoroughly and clearly as possible
  • Pay special attention to the title, results, platforms where the bug occurs, and if the bug happens on staging/production.
• I have reviewed and subscribed to the linked Slack conversation to ensure Slack/Github stay in sync

[dubielzyk-expensify]

Added some progress here