HttT S17: Add po comment

(cherry picked from commit b7c431e)

data/campaigns/Heir_To_The_Throne/scenarios/17_Scepter_of_Fire.cfg

@@ -633,6 +633,7 @@
             [then]
                 [message]
                     race=dwarf
+                    # po: "loess" is a term for sediment deposited by wind.
                     message=_ "Lord Konrad, yon rumble was made by nae enemy o’ us. ’Tis the echoes of the very bedrock witherin’ and crumbling beneath us that we ’eard. Are ye feeling naught heat and loess redoubling around us? I beseech that we not tarry ’ere any more than we ha’ to, lest the forming abysses claim us."
                 [/message]
             [/then]