Fix object-literal-sort-keys description

[stefanhamburger]

PR checklist

• Addresses an existing issue: #0000
• New feature, bugfix, or enhancement
  • Includes tests
• Documentation update

Overview of change:

Fixed the Markdown in the options description of the object-literal-sort-keys rule:

• Indent text under the match-declaration-order option
• Display code samples as code instead of raw text
• Display config options in monospace text

There is an open pull request for this rule (#2831) but it is already lagging behind the master branch, so merging this PR won't interfere there. However, the PRs #3748 and #4193 will need to be updated.

CHANGELOG.md entry:

[no-log] [docs] Fix object-literal-sort-keys formatting

[JoshuaKGoldberg]

Thanks @stefanhamburger!