fix(item-sliding): fix the item options visibility and wrap the button

- updates documentation
- renames `getSlidingPercent` to `getSlidingRatio `
- adds expandable as a property to option
- renames classes and updates styles
- fixes a bug where active class wasn’t being removed on drag end

references #13993

packages/core/src/components.d.ts

@@ -1314,6 +1314,7 @@ declare global {
     export interface IonItemOptionAttributes extends HTMLAttributes {
       color?: string;
       disabled?: boolean;
+      expandable?: boolean;
       href?: string;
       mode?: 'ios' | 'md';
     }