typo fix

Author: BB

advection/advection-higherorder.tex

@@ -45,7 +45,7 @@ \section{Advection and the finite-volume method}
 that it updates in time based on the fluxes through the boundary of
 the zone.
 
-We now have a choice on how to proceed with the time-discretiation:
+We now have a choice on how to proceed with the time-discretization:
 \begin{enumerate}
 \item We can discretize ${\partial a_i}/{\partial t}$ directly as
   $(a_i^{n+1} - a_i^n)/\Delta t$.  Then to achieve second-order