Temporary revert moving CharSequence.charAt because of markdown parser

libraries/stdlib/src/kotlin/collections/DeprecatedBuiltins.kt

@@ -30,9 +30,6 @@ public fun <K, V> Map.Entry<K, V>.getKey(): K = key
 @Deprecated("Use property 'value' instead", ReplaceWith("this.value"))
 public fun <K, V> Map.Entry<K, V>.getValue(): V = value
 
-@Deprecated("Use operator 'get' instead", ReplaceWith("this[index]"))
-public fun CharSequence.charAt(index: Int): Char = this[index]
-
 @Deprecated("Use 'removeAt' instead", ReplaceWith("this.removeAt(index)"))
 public fun <E> MutableList<E>.remove(index: Int): E = removeAt(index)
 

libraries/stdlib/src/kotlin/collections/MutableCollections.kt

@@ -3,6 +3,9 @@
 
 package kotlin
 
+@Deprecated("Use operator 'get' instead", ReplaceWith("this[index]"))
+public fun CharSequence.charAt(index: Int): Char = this[index]
+
 /**
  * Adds the specified [element] to this mutable collection.
  */