Irregular section titles: Additional Properties of the Object/String/Date/RegExp.prototype Object

[foolip]

This is an editorial issue. The spec has 4 sections whose naming departs from the rest:

• Additional Properties of the Object.prototype Object
• Additional Properties of the String.prototype Object
• Additional Properties of the Date.prototype Object
• Additional Properties of the RegExp.prototype Object

In all the rest of the spec, sections are instead named "(Additional/Something) Properties of the Something Prototype Object", including the sections which these are additional to, like Properties of the String Prototype Object.

If the IDs can be preserved, renaming the sections would make for more consistency.

This isn't a big issue, but is something I noticed while trying to pattern match the TOC of the spec, see https://es.discourse.group/t/is-the-api-surface-of-the-spec-machine-readable/699.