Add some XML doc comments

Author: paulirwin

src/Lucene.Net.Grouping/AbstractAllGroupsCollector.cs

@@ -34,7 +34,6 @@ namespace Lucene.Net.Search.Grouping
     /// @lucene.experimental
     /// </summary>
     /// <typeparam name="TGroupValue"></typeparam>
-    // ReSharper disable once RedundantExtendsListEntry
     public abstract class AbstractAllGroupsCollector<TGroupValue> : IAbstractAllGroupsCollector
     {
         /// <summary>
@@ -92,6 +91,9 @@ public virtual void SetScorer(Scorer scorer)
 
         #region Explicit interface implementations
 
+        /// <summary>
+        /// LUCENENET specific method to provide an object-based implementation of <see cref="Groups"/>.
+        /// </summary>
         ICollection<object> IAbstractAllGroupsCollector.Groups => new CastingCollectionAdapter<TGroupValue, object>(Groups);
 
         #endregion

src/Lucene.Net.Grouping/AbstractDistinctValuesCollector.cs

@@ -117,8 +117,14 @@ protected GroupCount(TGroupValue groupValue) // LUCENENET: CA1012: Abstract type
 
             #region Explicit interface implementations
 
+            /// <summary>
+            /// LUCENENET specific method to provide an object-based implementation of <see cref="GroupValue"/>.
+            /// </summary>
             object IGroupCount.GroupValue => GroupValue;
 
+            /// <summary>
+            /// LUCENENET specific method to provide an object-based implementation of <see cref="UniqueValues"/>.
+            /// </summary>
             ISet<object> IGroupCount.UniqueValues => new CastingSetAdapter<TGroupValue, object>(UniqueValues);
 
             #endregion

src/Lucene.Net.Grouping/AbstractFirstPassGroupingCollector.cs

@@ -423,6 +423,12 @@ public virtual void SetNextReader(AtomicReaderContext context)
 
         #region Explicit interface implementations
 
+        /// <summary>
+        /// LUCENENET specific method to provide an <see cref="ISearchGroup"/>-based implementation of <see cref="GetTopGroups(int, bool)"/>.
+        /// </summary>
+        /// <param name="groupOffset">The offset in the collected groups</param>
+        /// <param name="fillFields">Whether to fill to <see cref="ISearchGroup.SortValues"/></param>
+        /// <returns>top groups, starting from offset</returns>
         ICollection<ISearchGroup> IAbstractFirstPassGroupingCollector.GetTopGroups(int groupOffset, bool fillFields)
         {
             var topGroups = GetTopGroups(groupOffset, fillFields);

src/Lucene.Net.Grouping/AbstractSecondPassGroupingCollector.cs

@@ -148,6 +148,11 @@ public virtual TopGroups<TGroupValue> GetTopGroups(int withinGroupOffset)
 
         #region Explicit interface implementations
 
+        /// <summary>
+        /// LUCENENET specific method to provide an <see cref="ITopGroups"/>-based implementation of <see cref="GetTopGroups(int)"/>.
+        /// </summary>
+        /// <param name="withinGroupOffset">The offset within each group</param>
+        /// <returns>The top groups</returns>
         ITopGroups IAbstractSecondPassGroupingCollector.GetTopGroups(int withinGroupOffset)
             => GetTopGroups(withinGroupOffset);