Fix unresolved MapConfig XML doc cref in ChildContextConfig

MapConfig is now generic (MapConfig<TItem>), so the bare <see cref="MapConfig"/>
no longer resolved and broke the build under TreatWarningsAsErrors (CS1574).
Reference the generic type as MapConfig{TItem}.

Author: GarrettBeatty

Libraries/src/Amazon.Lambda.DurableExecution/ChildContextConfig.cs

@@ -47,7 +47,7 @@ public sealed class ChildContextConfig
     /// </para>
     /// <para>
     /// This mirrors the <c>NestingType.Flat</c> option on
-    /// <see cref="MapConfig"/> and <see cref="ParallelConfig"/>, letting a
+    /// <see cref="MapConfig{TItem}"/> and <see cref="ParallelConfig"/>, letting a
     /// standalone <see cref="IDurableContext.RunInChildContextAsync{T}(System.Func{IDurableContext, System.Threading.CancellationToken, System.Threading.Tasks.Task{T}}, string?, ChildContextConfig?, System.Threading.CancellationToken)"/>
     /// call opt into virtual contexts — for example when manually fanning out
     /// work and awaiting the returned tasks with <c>Task.WhenAll</c>.