Preferences: Improve label and tooltip of 'Accelerated speed' slider.

(cherry-picked from commit d95efd3409)

data/gui/window/preferences/01_general.cfg

@@ -80,12 +80,12 @@
 			horizontal_grow = true
 			{_GUI_PREFERENCES_CHECKBOX_ALIGN_BORDER}
 			{_GUI_PREFERENCES_MAIN_COMPOSITE_SLIDER
-				( _ "Speed:")
+				( _ "Acceleration factor:")
 				turbo_slider (
 					# Starts at 0 since the slider values are used for vector index access.
 					minimum_value,maximum_value=0,11
 					step_size=1
-					tooltip= _ "Units move and fight speed"
+					tooltip= _ "Speed at which unit moves and animations play when 'Accelerated speed' is enabled."
 				)
 			}
 		[/column]