[docs] fix formatting in presto-cpp/features.rst

[steveburnett]

Description

Fix formatting errors in presto-cpp/features.rst that create the following warnings in local doc build:

/Users/steveburnett/Documents/GitHub/presto/presto-docs/src/main/sphinx/presto_cpp/features.rst:277: WARNING: Title underline too short.

``native_debug_disable_expression_with_peeling``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
/Users/steveburnett/Documents/GitHub/presto/presto-docs/src/main/sphinx/presto_cpp/features.rst:277: WARNING: Title underline too short.

``native_debug_disable_expression_with_peeling``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
/Users/steveburnett/Documents/GitHub/presto/presto-docs/src/main/sphinx/presto_cpp/features.rst:297: WARNING: Title underline too short.

``native_debug_disable_expression_with_memoization``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
/Users/steveburnett/Documents/GitHub/presto/presto-docs/src/main/sphinx/presto_cpp/features.rst:297: WARNING: Title underline too short.

``native_debug_disable_expression_with_memoization``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
/Users/steveburnett/Documents/GitHub/presto/presto-docs/src/main/sphinx/presto_cpp/features.rst:308: WARNING: Title underline too short.

``native_debug_disable_expression_with_lazy_inputs``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
/Users/steveburnett/Documents/GitHub/presto/presto-docs/src/main/sphinx/presto_cpp/features.rst:308: WARNING: Title underline too short.

``native_debug_disable_expression_with_lazy_inputs``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Motivation and Context

Builds on work in #23210, #23090, #23033, #22876, and #22985.

Like the doc build errors I fixed in the other PRs, these errors don't stop the build but they're annoying, and these are easy and low-risk fixes.

Impact

Reduces warnings in doc builds, making them run faster.

Test Plan

Local doc builds.

Before:
Six errors above display, and total build succeeded, 19 warnings.

After: The six errors are not displayed, and total build succeeded, 13 warnings.

Contributor checklist

• Please make sure your submission complies with our development, formatting, commit message, and attribution guidelines.
• 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 ==