put more focus/detail on slots API

Author: amandaesmith3

docs/react/quickstart.md

@@ -207,7 +207,7 @@ Here in our `IonContent`, we're adding an `IonList` and a much more involved `Io
 </IonItem>
 ```
 
-Item is important as it clearly shows the mix of React concepts and Web Component concepts. From the Web Components side, we have a special attribute called `slot`. This is key for letting the `IonItem` know where to place the `IonBadge` when it renders. This is not a React API, but a web standards API.
+Looking at our code, we have a special attribute called `slot`. This is key for letting the `IonItem` know where to place the `IonBadge` when it renders. This is not a React API, but a web standards API, and it is used in many Ionic Framework components. (For more information on slots, see the MDN docs [here](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/slot).)
 
 Let's look at another component from Ionic, FAB. Floating Action Buttons are a nice way to provide a main action that is elevated from the rest of an app. For this FAB, we'll need three components: a FAB, a FAB Button, and an Icon.
 

docs/vue/quickstart.md

@@ -321,7 +321,7 @@ Here in our `IonContent`, we are adding an `IonList` and a much more involved `I
 </ion-item>
 ```
 
-Looking at our code, we have a special attribute called slot. This is key for letting the `IonItem` know where to place the `IonBadge` when it renders. This is not a Vue API, but a web standards API. Additionally, this is different from the slots API you may recall from Vue 2.
+Looking at our code, we have a special attribute called `slot`. This is key for letting the `IonItem` know where to place the `IonBadge` when it renders. This is not a Vue API, but a web standards API, and it is used across many Ionic Framework components. Additionally, this is different from the slots API you may recall from Vue 2. (For more information on slots, see the MDN docs [here](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/slot).)
 
 Let's look at another component from Ionic Framework, FAB. Floating Action Buttons are a nice way to provide a main action that is elevated from the rest of an app. For this FAB, we will need three components: a FAB, a FAB Button, and an Icon.