chore: Use <mark> element for filtering highlights

[avinashbot]

Description

<mark> indicates a portion of the document's content which is likely to be relevant to the user's current activity. This might be used, for example, to indicate the words that matched a search operation. (MDN)

Now you know!

Related links, issue #, if available: AWSUI-60213

How has this been tested?

It's an HTML element change - ideally, it should slip past our tests and any tests for those that use the components.

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.44%. Comparing base (a07a737) to head (02e9dc6).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #3249    +/-   ##
========================================
  Coverage   96.44%   96.44%            
========================================
  Files         791      791            
  Lines       22563    22563            
  Branches     7381     7788   +407     
========================================
  Hits        21760    21760            
  Misses        796      796            
  Partials        7        7            

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