Update src/callbacks_step/glm_speed.jl

Co-authored-by: Andrew Winters <[email protected]>

src/callbacks_step/glm_speed.jl

@@ -14,8 +14,8 @@ The `cfl` number should be set to the same value as for the time step size calcu
 `glm_scale` ensures that the GLM wave speed is lower than the fastest physical waves in the MHD
 solution and should thus be set to a value within the interval [0,1]. Note that `glm_scale = 0`
 deactivates the divergence cleaning.
-In case of a couplings semidiscretization specify for which semi_index the divergence
-cleaning should be applied to.
+In case of coupling semidiscretizations, specify for which semi_index the divergence
+cleaning should be applied.
 """
 struct GlmSpeedCallback{RealT <: Real}
     glm_scale::RealT