Clarifying "text node" definition (step 2G)

[rahimabdi]

In "4.3.2 Computation steps", Step 2G of the name computation algorithm states:

G. Text Node: Otherwise, if the current node is a Text Node, return its textual contents.

Although a "Node" definition is provided, it's not made explicit what a "text node" is. I would propose adding more documentation, e.g.,:

• The DOM spec "Text" interface definition: https://dom.spec.whatwg.org/#interface-text
• Also the "Node" interface, rather than linking to the Node tree definition: https://dom.spec.whatwg.org/#interface-node

Other sections that would need updating with linked "node" references:

• 4 Name and Description
• 4.3 Text Equivalent Computation

Further clarification from @cookiecrook and additional context for why this is being recommended in web-platform-tests/wpt#42407 (comment):

These are inherited from XML/DOM terms: most commonly text node versus element node versus comment node. Element nodes can be empty or contain other element, comment, and text nodes, but IIRC text nodes and comment nodes are always leaf nodes.

[jnurthen]

Competing text node definitions:

• https://dom.spec.whatwg.org/#dom-node-text_node {{Node/TEXT_NODE}}
• https://drafts.csswg.org/css-display-4/#text-nodes [=CSS/text node=]