Expand config parameter location explanation (#2518)
Expand config parameter location explanation (#2518)

* Expand config parameter location explanation

* Further explains how and where shell script parameters should be injected
* Follow on from #2506
* Part 2 of #2129

Signed-off-by: Morgan Davies <a6c48ac807a6f6af0e502138d851246d0dddd3ec@gmail.com>
Co-authored-by: Stewart X Addison <93bad89180e3305bab30ac52e47c4eafb9ba8060@users.noreply.github.com>
AdoptOpenJDK/openjdk-build,AdoptOpenJDK/openjdk-build