Minor doc fix
Minor doc fix

--HG--
branch : Scott_P/minor-doc-fix-1474248180814

jvgomez/ompl,utiasASRL/batch-informed-trees,utiasASRL/batch-informed-trees,davetcoleman/ompl,utiasASRL/batch-informed-trees,davetcoleman/ompl,jvgomez/ompl,davetcoleman/ompl,utiasASRL/batch-informed-trees,florianhauer/ompl,florianhauer/ompl,jvgomez/ompl,florianhauer/ompl,utiasASRL/batch-informed-trees,jvgomez/ompl,florianhauer/ompl,jvgomez/ompl,davetcoleman/ompl,utiasASRL/batch-informed-trees,davetcoleman/ompl,jvgomez/ompl,davetcoleman/ompl,florianhauer/ompl,florianhauer/ompl