Servo on Nostr: - Fix iframe resize visibility so that size changes are now immediately observable in ...

- Fix iframe resize visibility so that size changes are now immediately observable in the child document, matching other engines
- Created DOM element types for SVG shapes, gradients, and structural elements including `<circle>`, `<ellipse>`, `<rect>`, `<path>`, `<polygon>`, `<polyline>`, `<line>`, `<linearGradient>`, `<radialGradient>`, `<stop>`, `<g>`, `<defs>`, `<symbol>`, and `<use>`