Shorten every instance of "CHANNEL" to "C" and whisper too

To save a little space in messages, it's getting very cramped

Modules/AgentTracker.lua

@@ -6,6 +6,7 @@ local ModuleName = "AgentTracker"
 ---@diagnostic disable-next-line: missing-fields
 shared.AgentTracker = {}
 function shared.AgentTracker.Init()
+	--/run Heimdall_Data.config.agents["Cyheuraeth"]=date("%Y-%m-%dT%H:%M:%S")
 	---@type table<string, boolean>
 	local channelRosterFrame = CreateFrame("Frame")
 	channelRosterFrame:RegisterEvent("CHANNEL_ROSTER_UPDATE")