Added original question to question rewriter

Author: alkampfergit

src/KernelMemory.Extensions.FunctionalTests/QueryPipeline/UserQuestionConversationTests.cs

@@ -68,6 +68,17 @@ public void Can_continue_conversation_with_unanswered_question()
         Assert.False(question.Answered);
     }
 
+    [Fact]
+    public void Original_question_is_saved_when_rewriting_question()
+    {
+        var sut = GenerateSut("What is water");
+
+        sut.RewriteQuestion("What is the color of the sky");
+
+        Assert.Equal("What is water", sut.OriginalQuestion);
+        Assert.Equal("What is the color of the sky", sut.Question);
+    }
+
     [Fact]
     public void Can_add_saved_conversation_to_userQuestion() 
     {

src/KernelMemory.Extensions/QueryPipeline/UserQuestion.cs

@@ -33,6 +33,11 @@ internal void AddReRanker(IReRanker reRanker)
 
     public string Question { get; private set; }
 
+    /// <summary>
+    /// if the question was rewritten, this stores the original question made by the user.
+    /// </summary>
+    public string OriginalQuestion { get; private set; }
+
     /// <summary>
     /// Optional list of filter to perform the query.
     /// </summary>
@@ -193,6 +198,7 @@ public void SetConversation(Conversation conversation)
 
     public void RewriteQuestion(string newQuestion) 
     {
+        OriginalQuestion = Question;
         Question = newQuestion;
     }