Fixing the Navigation is not working in the blog in Japanese

[Deepak-cell311]

Closes #1614

What kind of change does this PR introduce?

This PR fixes a bug where in-page navigation (e.g., table of contents or anchor links) was not working in the Japanese version of the blog. The root cause was that the slugifyMarkdownHeadline function did not correctly handle non-Latin characters like Japanese, resulting in empty or malformed slugs.

Checklist

• I have linked a related issue using Closes #1614
• I have described the kind of change made
• I have tested the feature in both English and Japanese blog versions
• I have ensured slugs generate correctly for Unicode characters
• I have verified anchor links are working as expected

@benjagm

[github-actions]

Hi @Deepak-cell311! Thanks a lot for your contribution!

I noticed that the following required information is missing or incomplete: issue reference, kind of change description

Please update the PR description to include this information. You can find placeholders in the PR template for these items.

Thanks a lot!

[github-actions]

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Name	Status	Preview	Last Commit
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (b68db4b) to head (a67c7b1).
Report is 13 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #1642   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           10        10           
  Lines          396       396           
  Branches       106       106           
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  Hits           396       396           

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[Deepak-cell311]

Hi @DhairyaMajmudar ,
Kindly have a look over and review this PR whenever you have a moment.
Thank you🚀