Fix SA1515,1616: provide comments on return

src/Microsoft.Restier.Core/Query/QueryRequest.cs

@@ -54,6 +54,9 @@ public QueryRequest(IQueryable query, bool? includeTotalCount = null)
         /// Indicates if the total number of items should be retrieved
         /// when the result has been filtered using paging operators.
         /// </param>
+        /// <returns>
+        /// The created instance of the <see cref="QueryRequest"/> class.
+        /// </returns>
         public static QueryRequest Create<TElement, TResult>(
             IQueryable<TElement> query,
             Expression<Func<IQueryable<TElement>, TResult>> singularExpression,
@@ -78,6 +81,9 @@ public static QueryRequest Create<TElement, TResult>(
         /// Indicates if the total number of items should be retrieved
         /// when the result has been filtered using paging operators.
         /// </param>
+        /// <returns>
+        /// The created instance of the <see cref="QueryRequest"/> class.
+        /// </returns>
         public static QueryRequest Create(
             IQueryable query,
             LambdaExpression singularExpression,

src/Microsoft.Restier.Core/Submit/ChangeSetEntry.cs

@@ -34,7 +34,9 @@ internal ChangeSetEntry(ChangeSetEntryType type)
         /// <summary>
         /// Indicates if this change set entry is in a changed state.
         /// </summary>
-        /// <returns></returns>
+        /// <returns>
+        /// If this change set entry is in a changed state.
+        /// </returns>
         public bool HasChanged()
         {
             return this.ChangeSetEntityState == DynamicChangeSetEntityState.Changed ||
@@ -425,6 +427,9 @@ public ActionInvocationEntry(
         /// <summary>
         /// Gets an array of the arguments to pass to the action.
         /// </summary>
+        /// <returns>
+        /// An array of the arguments to pass to the action.
+        /// </returns>
         public object[] GetArgumentArray()
         {
             if (this.Arguments == null)

src/Microsoft.Restier.Core/Submit/ValidationResult.cs

@@ -39,6 +39,9 @@ public class ValidationResult
         /// <summary>
         /// Returns the string that represents this validation result.
         /// </summary>
+        /// <returns>
+        /// The string that represents this validation result.
+        /// </returns>
         public override string ToString()
         {
             return this.Message;