README.adoc: copy-edit
README.adoc: copy-edit

The README.adoc file was translated from README.md using pandoc.

However, pandoc did not get the translation completely correct, and so
there are some mistakes here and there.

Copy-edit README.adoc by reading through it, comparing it with
README.md, and correcting the errors.

se-edu/addressbook-level1,se-edu/addressbook-level1