Interpolation now renders text nodes.

[koculu]

Summary

Removes generated interpolation <span> elements from the rendered DOM while preserving the existing fast interpolation binding pipeline.

Changes

• Keep interpolation preprocessing based on generated internal r-text spans for fast element-only directive collection.
• Mark generated interpolation spans with internal r-rgi.
• Update r-text so marked interpolation spans are replaced with direct Text nodes during mount.
• Move bind cleanup data from the generated span to the replacement text node so reactivity and unbind still work correctly.
• Preserve normal user-authored r-text elements.
• Add replaceChild support to minidom and switch interpolation span replacement to use it.
• Update tests that previously asserted generated span output.
• Remove stale docs wording that described mixed interpolation as generated <span r-text> nodes.