Support Sphinx 6 and fix processing of attribute-link

What's Changed

• Process attribute-link during consistency check event by @gcrabbe in #330
• Minor refactoring of ItemAttributesMatrix by @JasperCraeghs in #329
• Update requirement version syntax by @JasperCraeghs in #335
• Update actions due to deprecation warning by @Letme in #334
• Update sphinx requirement from >=2.1,<6.0 to >=2.4,<7.0 by @dependabot in #333
• Avoid sphinxcontrib.jquery==3.0.0 and enable plugin by @JasperCraeghs in #336

New Contributors

• @dependabot made their first contribution in #333

Full Changelog: v9.5.1...v9.6.0