Fix a lintian informational message about a typo in the source program.
--- a/source/dat/clua/dungeon.lua
+++ b/source/dat/clua/dungeon.lua
@@ -357,7 +357,7 @@
   end
 end
 
--- Turn persistant data into a human readable string.
+-- Turn persistent data into a human readable string.
 function persist_to_string()
     return table_to_string(dgn.persist)
 end
\ No newline at end of file
