remove Assert preventing registration of multiple nested paths

SimpleHttpServer/Types/PathTree.cs

@@ -84,17 +84,14 @@ internal class PathTree<T> where T : class {
                     catchAllNext.AddSuccessor(segments[1..], newLeafData);
                     return;
                 } else { // must be single wildcard otherwise                    
-                    Assert(pathWildcardNext == null);
-                    pathWildcardNext = new();
+                    pathWildcardNext ??= new();
                     pathWildcardNext.AddSuccessor(segments[1..], newLeafData);
                     return;
                 }
             }
 
             // otherwise we want to add a new constant path successor
-            if (next == null) {
-                next = new();
-            }
+            next ??= new();
 
             if (next.TryGetValue(seg, out var existingNode)) {
                 existingNode.AddSuccessor(segments[1..], newLeafData);