add eternal darkness spell

spells.tex

@@ -560,6 +560,22 @@ As long as you have both of those at level 2 or above, you can cast the spell.
 
 \showSpells{Light3}
 
+\spell{Eternal Night}% Name
+  {Devious, Duplicated}% Enhancements
+  {Wane}% Action
+  {Fire, Air}% Spheres
+  {\roll{Intelligence}{Wyldcrafting}}% Resist with
+  {The caster pulls on a memory of seeing darkness at the bottom of a clear loch, and the darkness comes.
+  After two \glsfmtplural{interval}, a patch of darkness forms, 5~\glsfmtplural{step} across.
+  Within four \glsfmtplural{interval}, all vision suffers a -4 Penalty}% Description
+  {
+  \Glspl{witch} commonly use this spell to make anyone in \pgls{bothy} or other sleeping-space miss the day.
+  They awaken late, in darkness, and generally assume they simply cannot sleep.
+  After all, they can see darkness, so it must be night, not day.
+
+  By the time people start to question their sanity, and light a fire, the next night may have already come.
+  }
+
 \subsection{Mind}
 
 \label{carrierCrow}