Lower DocumentMemoryMinRelevance from 0.8 to 0.66 (#1006)

### Motivation and Context
We want relevant files to be included.

### Description
Lower DocumentMemoryMinRelevance from 0.8 to 0.66

webapi/Options/PromptsOptions.cs

@@ -37,13 +37,13 @@ public class PromptsOptions
     internal double MemoriesResponseContextWeight { get; } = 0.6;
 
     /// <summary>
-    /// Upper bound of the relevancy score of a kernel memory to be included in the final prompt.
+    /// Upper bound of relevance score of a kernel memory to be included in the final prompt.
     /// The actual relevancy score is determined by the memory balance.
     /// </summary>
     internal float SemanticMemoryRelevanceUpper { get; } = 0.9F;
 
     /// <summary>
-    /// Lower bound of the relevancy score of a kernel memory to be included in the final prompt.
+    /// Lower bound of relevance score of a kernel memory to be included in the final prompt.
     /// The actual relevancy score is determined by the memory balance.
     /// </summary>
     internal float SemanticMemoryRelevanceLower { get; } = 0.6F;
@@ -52,7 +52,7 @@ public class PromptsOptions
     /// Minimum relevance of a document memory to be included in the final prompt.
     /// The higher the value, the answer will be more relevant to the user intent.
     /// </summary>
-    internal float DocumentMemoryMinRelevance { get; } = 0.8F;
+    internal float DocumentMemoryMinRelevance { get; } = 0.66F;
 
     // System
     [Required, NotEmptyOrWhitespace] public string KnowledgeCutoffDate { get; set; } = string.Empty;