projects/chat: Make generated vdl go code say "vanadium vdl tool".
projects/chat: Make generated vdl go code say "vanadium vdl tool".

Change-Id: I9d8edc2a070e8f66f83f56b4088a8cc400aacd55

vanadium/chat,viksit/chat,viksit/chat,vanadium/chat,viksit/chat,vanadium/chat,viksit/chat,vanadium/chat,viksit/chat,vanadium/chat