Improper heading levels on code of conduct page

[jchristgit]

As pointed out in #1363:

There are multiple h1 tags, many jumps in sequence, and several subheadings that are not associated with the parent heading.

Headings convey important semantic information to assistive technology users, helping to understand the structure and organization of the page. Heading level 1 represents the main topic of the page, heading level 2 is a sub-topic of that main heading, heading level 3 as a sub-topic of the heading level 2, etc. Headings should be sequential and follow the intended hierarchy of information. Rather than choosing headings for the purpose of a visual presentation, headings can be styled with stylesheets. Refer to https:www.a11yproject.com/posts/how- to-accessible-heading-structure for more information.