Fix typo in runtests.jl message

No effect on code behavior.

Author: lamorton

test/runtests.jl

@@ -1,6 +1,6 @@
 using SafeTestsets, Test
 
-@safetestset "Varialbe scope tests" begin include("variable_scope.jl") end
+@safetestset "Variable scope tests" begin include("variable_scope.jl") end
 @safetestset "Symbolic parameters test" begin include("symbolic_parameters.jl") end
 @safetestset "Parsing Test" begin include("variable_parsing.jl") end
 @safetestset "Simplify Test" begin include("simplify.jl") end