[PATCH] ReleaseNotes.xml: Update credits section for 7.6 RC1

[Alan Coopersmith]

The list of people to credit in this release was created by running
the script at https://gist.github.com/671819 with my current list of
katamari modules/versions to get a unified ChangeLog for all katamari
modules.   For xcb modules, since this is their first inclusion, this
went back to the dawn of the xcb project.