Release notes for Inweb v7.2.0

This release was made in August 2022, and was the first proper release for major version 7. This release is the baseline for Inweb release notes from here on.

The prerelease version v7.1.0, a stopgap during the period when Inform's open-sourcing was getting going, is substantially the same program. However, 7.2.0 corrects a few bugs, and the foundation library added a number of useful functions, notably to do with JSON file parsing and validation.