1. document api: createelement

2. document api: createelementns

3. document api: createelementns: emoji and more unicode in element and attribute names and namespace prefix (valid names match html parser)

4. document api: createelementns: `options` parameter

5. document api: createelementns: `options` parameter: `customelementregistry` option

6. document api: createelementns: `options` parameter: `is` option

7. document api: createelement: emoji and more unicode in element and attribute names and namespace prefix (valid names match html parser)

8. document api: createelement: `options` parameter

9. document api: createelement: `options` parameter: `customelementregistry` option

10. document api: createelement: `options` parameter: `is` parameter