update src folder links

[Arhell]

Q	A
Is bugfix?	✔️/❌
New feature?	✔️/❌
Breaks BC?	✔️/❌
Fixed issues	resolve https://github.com/yiisoft/html/issues/189

[what-the-diff[bot]]

PR Summary

• Updated URL for Boolean Attributes in Html.php The reference link for understanding Boolean attributes used in our HTML structure has been updated to use 'https' for secure site access. New Link: https://www.w3.org/TR/html5/infrastructure.html#boolean-attributes.

• Updated URL for Void Elements in CustomTag.php The code in CustomTag.php includes a URL for understanding 'void elements'. This link has now been updated to use 'https'. Enhanced security in browsing is expected. New Link: https://www.w3.org/TR/html-markup/syntax.html#void-element.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (a698c84) 100.00% compared to head (78b0450) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #190 +/- ## =========================================== Coverage 100.00% 100.00% Complexity 775 775 =========================================== Files 85 85 Lines 2098 2098 =========================================== Hits 2098 2098 ```

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