fix title underline

[barm]

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have run the make format command to format my code
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have added my name and/or github handle to AUTHORS.rst
• I have added my change to CHANGES.rst
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #820 (d13cade) into master (67c7c43) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #820   +/-   ##
=======================================
  Coverage   97.87%   97.87%           
=======================================
  Files          18       18           
  Lines         988      988           
  Branches      150      150           
=======================================
  Hits          967      967           
  Misses          9        9           
  Partials       12       12           

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