update slider.md (facebook#1021)

update slider.md

Author: rickhanlonii

docs/slider.md

@@ -148,11 +148,11 @@ _This is not a controlled component_, you don't need to update the value during
 
 ### `thumbTintColor`
 
-Color of the foreground switch grip.
+The color used to tint the default thumb images on iOS, or the color of the foreground switch grip on Android.
 
-| Type               | Required | Platform |
-| ------------------ | -------- | -------- |
-| [color](colors.md) | No       | Android  |
+| Type               | Required |
+| ------------------ | -------- |
+| [color](colors.md) | No       |
 
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