fix(item): add detail prop, fix lines and styles

- removes item-block class
- fixes some styling with first/last-child
- adds detail prop to replace detail-none / detail-push attributes
- style the border and push arrow properly inside of an item with color

packages/core/src/components.d.ts

@@ -1475,6 +1475,7 @@ declare global {
   namespace JSXElements {
     export interface IonItemAttributes extends HTMLAttributes {
       color?: string;
+      detail?: boolean;
       disabled?: boolean;
       href?: string;
       mode?: 'ios' | 'md';