Fix a typo

Fix a typo

chapters/hpmor-chapter-078.tex

@@ -399,7 +399,7 @@ \chapter{Taboo Trade-offs Prelude: Cheating}
 
 The Sunshine Soldiers resumed their charge forward.
 
-Tracey yelled, her voice high with strain, “\emph{Inflammare!}” and the Sunshine charge came to another sudden halt as a line of fire blazed up between them in the half-dry grass, extending to follow the path of Tracey’s wand as she pointed it; an instant later Susan Bones cried “\emph{Finite Incantatem!}” and the flames dimmed, brightened, dimmed in the contest of their wills, other soldiers raising their wards to aim at Tracey; and \emph{that} was when Neville Longbottom plunged shrieking out of the sky.
+Tracey yelled, her voice high with strain, “\emph{Inflammare!}” and the Sunshine charge came to another sudden halt as a line of fire blazed up between them in the half-dry grass, extending to follow the path of Tracey’s wand as she pointed it; an instant later Susan Bones cried “\emph{Finite Incantatem!}” and the flames dimmed, brightened, dimmed in the contest of their wills, other soldiers raising their wands to aim at Tracey; and \emph{that} was when Neville Longbottom plunged shrieking out of the sky.
 
 \later