fix: minor corrections to ViewLocator implementation

- Update BindingGenerator XML doc to mention all three pipelines (A, B, C)
- Make DefaultViewLocator _lock instance-scoped instead of static since it only guards the per-instance _mappings dictionary

Author: glennawatson

src/ReactiveUI.Binding.SourceGenerators/BindingGenerator.cs

@@ -15,9 +15,10 @@ namespace ReactiveUI.Binding.SourceGenerators;
 
 /// <summary>
 /// The main incremental source generator entry point for ReactiveUI property observation and binding.
-/// Orchestrates two pipelines:
+/// Orchestrates three pipelines:
 /// Pipeline A (Type Detection): Detects notification mechanisms and generates high-affinity fallback binders.
 /// Pipeline B (Invocation Detection): Detects WhenChanged/WhenChanging/Bind calls and generates per-invocation code.
+/// Pipeline C (View Dispatch): Scans IViewFor&lt;T&gt; implementations and generates AOT-safe view locator dispatch.
 /// </summary>
 [Generator]
 public class BindingGenerator : IIncrementalGenerator

src/ReactiveUI.Binding/View/DefaultViewLocator.cs

@@ -13,21 +13,21 @@ namespace ReactiveUI.Binding;
 /// </summary>
 public sealed class DefaultViewLocator : IViewLocator
 {
-    /// <summary>
-    /// Synchronization lock for thread-safe access to mappings.
-    /// </summary>
-#if NET9_0_OR_GREATER
-    private static readonly Lock _lock = new();
-#else
-    private static readonly object _lock = new();
-#endif
-
     /// <summary>
     /// Source-generated dispatch function set by the generated code.
     /// Signature: (viewModelInstance, contract) returns IViewFor or null.
     /// </summary>
     private static Func<object, string, IViewFor?>? _generatedDispatch;
 
+    /// <summary>
+    /// Synchronization lock for thread-safe access to this instance's mappings.
+    /// </summary>
+#if NET9_0_OR_GREATER
+    private readonly Lock _lock = new();
+#else
+    private readonly object _lock = new();
+#endif
+
     /// <summary>
     /// Runtime explicit mappings from (viewModelType, contract) to view factory.
     /// Uses copy-on-write semantics for thread safety.