Adjust keyboard step to be something sensible

osu.Game/Screens/Edit/Timing/DifficultySection.cs

@@ -18,7 +18,8 @@ namespace osu.Game.Screens.Edit.Timing
             {
                 multiplierSlider = new SliderWithTextBoxInput<double>("Speed Multiplier")
                 {
-                    Current = new DifficultyControlPoint().SpeedMultiplierBindable
+                    Current = new DifficultyControlPoint().SpeedMultiplierBindable,
+                    KeyboardStep = 0.1f
                 }
             });
         }

osu.Game/Screens/Edit/Timing/SliderWithTextBoxInput.cs

@@ -69,6 +69,15 @@ namespace osu.Game.Screens.Edit.Timing
             }, true);
         }
 
+        /// <summary>
+        /// A custom step value for each key press which actuates a change on this control.
+        /// </summary>
+        public float KeyboardStep
+        {
+            get => slider.KeyboardStep;
+            set => slider.KeyboardStep = value;
+        }
+
         public Bindable<T> Current
         {
             get => slider.Current;