Fix typo in set_proposed_dt! docstring

Author: termi-official

src/integrator_interface.jl

@@ -157,8 +157,8 @@ function get_proposed_dt(i::DEIntegrator)
 end
 
 """
-    set_proposed_dt(i::DEIntegrator,dt)
-    set_proposed_dt(i::DEIntegrator,i2::DEIntegrator)
+    set_proposed_dt!(i::DEIntegrator,dt)
+    set_proposed_dt!(i::DEIntegrator,i2::DEIntegrator)
 
 Sets the proposed `dt` for the next timestep. If the second argument isa `DEIntegrator`, then it sets the timestepping of
 the first argument to match that of the second one. Note that due to PI control and step acceleration, this is more than matching