Change wallet address to match other examples, removing the .js prefix which could be confusing.

Remove deprecated methods for detecting support of a feature in a user agent.

Remove DOM query in favor of faster temporary element creation.

Prettier was changing the examples to its preferences. The specification should be consistent with other W3C standards' style.

https://www.w3.org/community/webed/wiki/Web_Education_community_group_style_guide#Code_standards

https://www.w3.org/wiki/Coding_style

The previous instructions did not work after the conversion to Astro, as Astro corrupts the includes and breaks the examples.

style: disable Prettier in the respec build script
docs: update spec local dev instructions to use the build script