Update: Expand sanitize_html_class() to support the full range of CDATA that a class attribute can contain.

[Debarghya-Banerjee]

Trac Ticket: Core-63156

Summary

This update addresses the TODO in the sanitize_html_class function to expand its support to the full range of characters allowed in a class attribute. Currently, the function only permits alphanumeric characters, hyphens, and underscores. The change will allow a broader set of characters, aligning with the HTML specification for class attributes.

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