Add summary for AbpCollectionExtensions.RemoveAll.

src/Volo.Abp.Core/System/Collections/Generic/AbpCollectionExtensions.cs

@@ -37,6 +37,13 @@ namespace System.Collections.Generic
             return true;
         }
 
+        /// <summary>
+        /// Removed all items from a collection those satisfy the given <paramref name="predicate"/>.
+        /// </summary>
+        /// <typeparam name="T">Type of the items in the collection</typeparam>
+        /// <param name="source">The collection</param>
+        /// <param name="predicate">The condition to remove the items</param>
+        /// <returns>List of removed items</returns>
         public static IList<T> RemoveAll<T>([NotNull] this ICollection<T> source, Func<T, bool> predicate)
         {
             var items = source.Where(predicate).ToList();