Fix broken link to syntax guide in default template

[Harjun751]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• DevOps
• Improve developer experience
• Others, please explain:

Resolves #2795

Overview of changes:
Updates the section to refer to the updated Syntax Overview page instead of the gone Full Syntax Reference page. Updates the relevant test.

Anything you'd like to highlight/discuss:

Testing instructions:

Proposed commit message: (wrap lines at 72 characters)

Fix link to user guide in default template

Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features
• Linked all related issues
• No unrelated changes

---

Reviewer checklist:

Indicate the SEMVER impact of the PR:

• Major (when you make incompatible API changes)
• Minor (when you add functionality in a backward compatible manner)
• Patch (when you make backward compatible bug fixes)

At the end of the review, please label the PR with the appropriate label: r.Major, r.Minor, r.Patch.

Breaking change release note preparation (if applicable):

• To be included in the release note for any feature that is made obsolete/breaking

Give a brief explanation note about:

• what was the old feature that was made obsolete
• any replacement feature (if any), and
• how the author should modify his website to migrate from the old feature to the replacement feature (if possible).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.73%. Comparing base (f02747b) to head (1a4e65d).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2799      +/-   ##
==========================================
+ Coverage   71.72%   71.73%   +0.01%     
==========================================
  Files         134      134              
  Lines        7299     7303       +4     
  Branches     1556     1552       -4     
==========================================
+ Hits         5235     5239       +4     
  Misses       1937     1937              
  Partials      127      127              

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