Formatted the headings of " A05 ❯ Multimedia Codecs Installation Guide"

[rl2939]

What does this pull request do?

This turns all but the first H1 on the page of https://wiki.almalinux.org/series/system/SystemSeriesA05.html into H2s.

Why?

Having more than one H1 per page messes with the structure of the page. This is also the only System Series article that is structured like this.