Fix dotnet#3898 (remove crefs to internal methods) (dotnet#3899)

Author: natke

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

@@ -49,7 +49,6 @@ namespace Microsoft.ML.Transforms
     /// ]]>
     /// </format>
     /// </remarks>
-    /// <seealso cref="TransformExtensionsCatalog.CopyColumns(TransformsCatalog, InputOutputColumnPair[])" />
     /// <seealso cref="TransformExtensionsCatalog.CopyColumns(TransformsCatalog, string, string)" />
     public sealed class ColumnCopyingEstimator : TrivialEstimator<ColumnCopyingTransformer>
     {

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

@@ -160,8 +160,6 @@ public sealed override SchemaShape GetOutputSchema(SchemaShape inputSchema)
     /// </remarks>
     /// <typeparam name="TKey">Specifies the key type.</typeparam>
     /// <typeparam name="TValue">Specifies the value type.</typeparam>
-    /// <seealso cref="ConversionsExtensionsCatalog.MapValue{TInputType, TOutputType}(TransformsCatalog.ConversionTransforms, IEnumerable{KeyValuePair{TInputType, TOutputType}}, InputOutputColumnPair[])"/>
-    /// <seealso cref="ConversionsExtensionsCatalog.MapValue{TInputType, TOutputType}(TransformsCatalog.ConversionTransforms, IEnumerable{KeyValuePair{TInputType, TOutputType[]}}, InputOutputColumnPair[])"/>
     /// <seealso cref="ConversionsExtensionsCatalog.MapValue{TInputType, TOutputType}(TransformsCatalog.ConversionTransforms, string, IEnumerable{KeyValuePair{TInputType, TOutputType}}, string, bool)"/>
     public sealed class ValueMappingEstimator<TKey, TValue> : ValueMappingEstimator
     {

src/Microsoft.ML.Transforms/RandomFourierFeaturizing.cs

@@ -622,7 +622,6 @@ private void TransformFeatures(in VBuffer<float> src, ref VBuffer<float> dst, Tr
     /// Check the See Also section for links to usage examples.
     /// ]]></format>
     /// </remarks>
-    /// <seealso cref="KernelExpansionCatalog.ApproximatedKernelMap(TransformsCatalog, ColumnOptions[])"/>
     /// <seealso cref="KernelExpansionCatalog.ApproximatedKernelMap(TransformsCatalog, string, string, int, bool, KernelBase, int?)"/>
     public sealed class ApproximatedKernelMappingEstimator : IEstimator<ApproximatedKernelTransformer>
     {