Add snippets for https://d.android.com/jetpack/compose/state - file r… (#45)

* Add snippets for https://d.android.com/jetpack/compose/state - file rename

Author: astamato

compose/snippets/src/main/java/com/example/compose/snippets/state/StateOverview.kt renamed to compose/snippets/src/main/java/com/example/compose/snippets/state/StateOverviewSnippets.kt

@@ -30,7 +30,6 @@ import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.Stable
-import androidx.compose.runtime.State
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -67,14 +66,6 @@ private fun HelloContent() {
 }
 // [END android_compose_state_overview]
 
-private object StateSnippetInterface {
-    // [START android_compose_state_interface]
-    interface MutableState<T> : State<T> {
-        override var value: T
-    }
-    // [END android_compose_state_interface]
-}
-
 private object StateSnippet1 {
     @OptIn(ExperimentalMaterial3Api::class)
     // [START android_compose_state_remember]