the spell and the name of the casting monster, rather than just "Unknown spell".
git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@8374 c06c8d41-db1a-0410-9941-cceddc491573
XM4TPQSKO43HMFRLUMDNRNXLTEZOYYY27ENCFTISYFFPZWUEPUQQC
DEBUGSTR("Unknown spell");
if (!is_valid_spell(real_spell))
DEBUGSTR("Invalid spell #%d cast by %s", (int) real_spell,
mons->name(DESC_PLAIN, true).c_str());
DEBUGSTR("Unknown monster spell '%s' cast by %s",
spell_title(real_spell),
mons->name(DESC_PLAIN, true).c_str());
return (beam);