applying the dotnet#3204 template to columnCopying.

Author: sfilipi

src/Microsoft.ML.Data/Transforms/ColumnCopying.cs

@@ -31,8 +31,18 @@
 namespace Microsoft.ML.Transforms
 {
     /// <summary>
-    /// <see cref="ColumnCopyingEstimator"/> copies the input column to another column named as specified in the parameters of the transformation.
+    /// Estimator creating the <see cref="ColumnCopyingTransformer"/>.
     /// </summary>
+    /// <remarks>
+    /// <format type="text/markdown"><![CDATA[
+    /// ### Estimator FAQ
+    /// | Question | Answer |
+    /// | -- | -- |
+    /// | Does this estimator need to look at the data to train its parameters? | No |
+    /// | Is the transformer created convertible to ONNX format? | Yes |
+    /// ]]>
+    /// </format>
+    /// </remarks>
     public sealed class ColumnCopyingEstimator : TrivialEstimator<ColumnCopyingTransformer>
     {
         [BestFriend]
@@ -67,6 +77,10 @@ public override SchemaShape GetOutputSchema(SchemaShape inputSchema)
         }
     }
 
+    /// <summary>
+    /// Transformer that creates a new column, named as specified in the output column name parameters, and
+    /// copies the data from the input column Name.
+    /// </summary>
     public sealed class ColumnCopyingTransformer : OneToOneTransformerBase
     {
         [BestFriend]

src/Microsoft.ML.Data/Transforms/ExtensionsCatalog.cs

@@ -51,11 +51,13 @@ internal static IReadOnlyList<InputOutputColumnPair> ConvertFromValueTuples((str
     public static class TransformExtensionsCatalog
     {
         /// <summary>
-        /// Copies the input column to another column named as specified in <paramref name="outputColumnName"/>.
+        /// Creates a <see cref="ColumnCopyingEstimator"/> that copies the data from the column specified in <paramref name="inputColumnName"/>
+        /// to a new column: <paramref name="outputColumnName"/>.
         /// </summary>
+        /// <remarks>For more information on this estimator see <see cref="ColumnCopyingEstimator"/>.</remarks>
         /// <param name="catalog">The transform's catalog.</param>
         /// <param name="outputColumnName">Name of the column resulting from the transformation of <paramref name="inputColumnName"/>.</param>
-        /// <param name="inputColumnName">Name of the columns to transform.</param>
+        /// <param name="inputColumnName">Name of the column to copy the data from.</param>
         /// <example>
         /// <format type="text/markdown">
         /// <![CDATA[
@@ -67,9 +69,11 @@ public static ColumnCopyingEstimator CopyColumns(this TransformsCatalog catalog,
             => new ColumnCopyingEstimator(CatalogUtils.GetEnvironment(catalog), outputColumnName, inputColumnName);
 
         /// <summary>
-        /// Copies the input column, name specified in the first item of the tuple,
-        /// to another column, named as specified in the second item of the tuple.
+        /// Creates a <see cref="ColumnCopyingEstimator"/> that copies the data from the column specified in <see cref="InputOutputColumnPair.InputColumnName" />
+        /// to a new column: <see cref="InputOutputColumnPair.OutputColumnName" />.
         /// </summary>
+        /// <remarks>This estimator can operate over several columns.
+        /// For more information on this estimator see <see cref="ColumnCopyingEstimator"/>.</remarks>
         /// <param name="catalog">The transform's catalog</param>
         /// <param name="columns">The pairs of input and output columns.</param>
         /// <example>