Remove extra copied doc comments. (#65)

diff --git a/lib/src/observable_map.dart b/lib/src/observable_map.dart
index b5c1f1b..6779246 100644
--- a/lib/src/observable_map.dart
+++ b/lib/src/observable_map.dart
@@ -20,21 +20,6 @@
 /// removed, or replaced, then observers that are listening to [changes]
 /// will be notified.
 class ObservableMap<K, V> extends Observable implements Map<K, V> {
-  /*
-     * Adapts [source] to be a `Map<K2, V2>`.
-   *
-   * Any time the set would produce a key or value that is not a [K2] or [V2],
-   * the access will throw.
-   *
-   * Any time [K2] key or [V2] value is attempted added into the adapted map,
-   * the store will throw unless the key is also an instance of [K] and
-   * the value is also an instance of [V].
-   *
-   * If all accessed entries of [source] are have [K2] keys and [V2] values
-   * and if all entries added to the returned map have [K] keys and [V]] values,
-   * then the returned map can be used as a `Map<K2, V2>`.
-   */
-
   /// Adapts [source] to be a `ObservableMap<K2, V2>`.
   ///
   /// Any time the map would produce a key or value that is not a [K2] or [V2]