[docs] Fix formatting in admin/cte-materialization.rst

[steveburnett]

Description

Fix formatting of unordered lists in admin/cte-materialization.rst.

Motivation and Context

Consistency in the formatting of Presto documentation.

Impact

Documentation.

Test Plan

Local doc build.

Before:

After:

Contributor checklist

• Please make sure your submission complies with our contributing guide, in particular code style and commit standards.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
• If release notes are required, they follow the release notes guidelines.
• Adequate tests were added if applicable.
• CI passed.

Release Notes

== NO RELEASE NOTE ==