doc/doxygen/chapters/optimize_performance.doxy: typo

doc/doxygen/chapters/optimize_performance.doxy

@@ -108,7 +108,7 @@ possibility according to task size, one can run
 speedup of independent tasks of very small sizes.
 
 The choice of scheduler also has impact over the overhead: for instance, the
- scheduler<c>dmda</c> takes time to make a decision, while <c>eager</c> does
+ scheduler <c>dmda</c> takes time to make a decision, while <c>eager</c> does
 not. <c>tasks_size_overhead.sh</c> can again be used to get a grasp at how much
 impact that has on the target machine.