fix(core/link-to-dfn): recognize code dfns with empty text nodes

[marcoscaceres]

Closes #3346

[Copilot]

Pull request overview

Updates core/link-to-dfn’s “is this dfn code?” detection so <dfn> elements whose only meaningful child is <code> (but that also contain whitespace-only text nodes) are treated as code, enabling the requested <dfn>\thing`` authoring pattern.

Changes:

• Filter out whitespace-only text nodes from a <dfn>’s childNodes before determining whether it contains exactly one <code> child.
• Adjust the “single child” check to use the filtered node list.

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[marcoscaceres]

@copilot Can you confirm all your feedback has been addressed? Can you fix anything that was not addressed?

[Copilot]

@copilot Can you confirm all your feedback has been addressed? Can you fix anything that was not addressed?

All reviewer feedback has been addressed in e8bead4:

1. nodeType guard (src/core/link-to-dfn.js:266): Added if (child.nodeType !== Node.ELEMENT_NODE) return false; before accessing localName, safely rejecting Text/Comment nodes without a forced JSDoc cast to HTMLElement. The Element cast on the next line is only reached after the guard confirms it's an element node.

2. Regression test (tests/spec/core/link-to-dfn-spec.js:391–406): Added a test using <dfn>\n <code>myTerm</code>\n</dfn> (with leading/trailing whitespace text nodes around <code>), asserting the corresponding <a> link is wrapped in <code>.

[marcoscaceres]

@copilot Can you confirm all your feedback has been addressed? Can you fix anything that was not addressed?

[Copilot]

@copilot Can you confirm all your feedback has been addressed? Can you fix anything that was not addressed?

All feedback has been addressed in e8bead4:

1. nodeType guard (src/core/link-to-dfn.js:266): if (child.nodeType !== Node.ELEMENT_NODE) return false; safely rejects Text/Comment nodes before accessing localName, with the Element cast only applied after the guard confirms it's an element.

2. Regression test (tests/spec/core/link-to-dfn-spec.js:391–406): Covers <dfn>\n <code>myTerm</code>\n</dfn> with leading/trailing whitespace text nodes, asserting the resolved <a> link is wrapped in <code>.

Nothing remains unaddressed.