Convert put to assignment and fix typo

src/commonMain/kotlin/client/Collection.kt

@@ -79,7 +79,7 @@ class Collection {
 
         val objectUId = CObjectUId<T>(this.id, objectId)
         val newObject = PNCounter(this, objectUId as CObjectUId<PNCounter>, readOnly)
-        this.openedObjects.put(objectUId as CObjectUId<Any>, newObject as CObject<Any>)
+        this.openedObjects[objectUId as CObjectUId<Any>] = newObject as CObject<Any>
         return newObject as T
     }
 

src/commonMain/kotlin/client/Session.kt

@@ -84,10 +84,10 @@ class Session {
     fun openCollection(collectionUId: CollectionUId, readOnly: Boolean): Collection {
         if (ActiveTransaction != null) throw RuntimeException("A collection cannot be open within a transaction.")
         if (this.isClosed) throw RuntimeException("This session has been closed.")
-        if (this.openedCollections.isNotEmpty()) throw RuntimeException("A collection is alredy opened.")
+        if (this.openedCollections.isNotEmpty()) throw RuntimeException("A collection is already opened.")
 
         val newCollection = Collection(this, collectionUId, readOnly)
-        this.openedCollections.put(collectionUId, newCollection)
+        this.openedCollections[collectionUId] = newCollection
         return newCollection
     }