Add documentation comments

lib/safe_area_values.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/widgets.dart';
 
+/// A data class that is used to pass safe area values for snackbar
 class SafeAreaValues {
   const SafeAreaValues({
     this.left = true,

lib/tap_bounce_container.dart

@@ -17,6 +17,7 @@ class TapBounceContainer extends StatefulWidget {
   TapBounceContainerState createState() => TapBounceContainerState();
 }
 
+/// State for a [TapBounceContainer].
 class TapBounceContainerState extends State<TapBounceContainer>
     with SingleTickerProviderStateMixin {
   late double _scale;

lib/top_snack_bar.dart

@@ -6,8 +6,10 @@ import 'package:top_snackbar_flutter/tap_bounce_container.dart';
 
 typedef ControllerCallback = void Function(AnimationController);
 
+/// Represents possible triggers to dismiss the snackbar.
 enum DismissType { onTap, onSwipe, none }
 
+/// Represents possible vertical position of snackbar.
 enum SnackBarPosition { top, bottom }
 
 OverlayEntry? _previousEntry;
@@ -44,10 +46,13 @@ OverlayEntry? _previousEntry;
 /// The [safeAreaValues] argument is used to specify the arguments of the
 /// [SafeArea] widget that wrap the snackbar.
 ///
-/// The [dismissType] argument specify which action to trigger to
+/// The [dismissType] argument specifies which action to trigger to
 /// dismiss the snackbar. Defaults to `TopSnackBarDismissType.onTap`
 ///
-/// The [dismissDirection] argument specify in which direction the snackbar
+/// The [snackBarPosition] argument specifies the vertical position of the snackbar.
+/// Defaults to [SnackBarPosition.top]
+///
+/// The [dismissDirection] argument specifies in which direction the snackbar
 /// can be dismissed. This argument is only used when [dismissType] is equal
 /// to `DismissType.onSwipe`. Defaults to `[DismissDirection.up]`
 void showTopSnackBar(