Correct exception on custom element re-definition

src/browser/webapi/CustomElementRegistry.zig

@@ -51,7 +51,8 @@ pub fn define(self: *CustomElementRegistry, name: []const u8, constructor: js.Fu
 
     const gop = try self._definitions.getOrPut(page.arena, name);
     if (gop.found_existing) {
-        return error.AlreadyDefined;
+        // Yes, this is the correct error to return when trying to redefine a name
+        return error.NotSupported;
     }
 
     const owned_name = try page.dupeString(name);

src/browser/webapi/DOMException.zig

@@ -47,7 +47,7 @@ pub fn getName(self: *const DOMException) []const u8 {
         .invalid_character_error => "InvalidCharacterError",
         .syntax_error => "SyntaxError",
         .not_found => "NotFoundError",
-        .not_supported => "NotSupported",
+        .not_supported => "NotSupportedError",
         .hierarchy_error => "HierarchyError",
     };
 }

src/browser/webapi/IntersectionObserver.zig

@@ -74,12 +74,7 @@ pub fn init(callback: js.Function, options: ?ObserverInit, page: *Page) !*Inters
         .array => |arr| try page.arena.dupe(f64, arr),
     };
 
-    return page._factory.create(IntersectionObserver{
+    return page._factory.create(IntersectionObserver{ ._callback = callback, ._root = opts.root, ._root_margin = root_margin, ._threshold = threshold });
-        ._callback = callback,
-        ._root = opts.root,
-        ._root_margin = root_margin,
-        ._threshold = threshold
-    });
 }
 
 pub fn observe(self: *IntersectionObserver, target: *Element, page: *Page) !void {

src/browser/webapi/net/Headers.zig

@@ -14,7 +14,6 @@ pub fn init(page: *Page) !*Headers {
     });
 }
 
-
 pub fn append(self: *Headers, name: []const u8, value: []const u8, page: *Page) !void {
     try self._list.append(page.arena, name, value);
 }