htmlreport: fix HTML validation and table column counts

[rgetz]

generated html reports were failing Nu Html Checker at https://validator.w3.org/

• Add space before checkbox attributes to comply with HTML5 standards.
• Remove trailing slashes from elements to prevent parser warnings.
• Correct colspan in summary and fileEntry tables from 5 to 6 to match header column count, preventing table validation warnings.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[firewave]

There currently is a HTML validation step using tidy in the CI. If you are aware of a different tool which is equivalent to the online validator feel free to mention it. It might also be possible that the current check is just misconfigured.

[rgetz]

While Tidy passes without errors or warnings, other validators (like Nu Html Checker) report issues. This is expected because:

• Tidy is more lenient
• Tidy primarily checks for well-formedness and common mistakes, and ignores some strict HTML5 rules.
• It allows some outdated syntax or minor structural issues (e.g., unquoted attributes, void element slashes) that modern validators consider errors.

Other validators are stricter. Tools like the Nu Html Checker enforce HTML5 conformance rigorously, including:

• Proper void element syntax ( not )
• Attribute quoting
• Table column consistency
• Inline event handler conventions

These stricter rules may generate warnings even though the tidy HTML “works” in browsers...

Check out:

• https://github.com/validator/validator
• run it on line at : https://validator.w3.org/#validate_by_upload

[firewave]

While Tidy passes without errors or warnings, other validators (like Nu Html Checker) report issues.

Thanks. I filed https://trac.cppcheck.net/ticket/14297 about replacing tidy.

[danmar]

@rgetz I would like to add your name in the AUTHORS file. which name would you like that I add?