Merge branch 'develop' into claude/todo-191-plan-508110

- ordered_map.hpp: develop's refactored members, with this branch's
  @sa links on every public member
- byte_container_with_subtype operator==/!= and ordered_map docs:
  develop's reviewed text (#5638); drop the now unreferenced examples
- basic_json.md: keep both version-history additions
- add the docset entries that develop's style check now requires for the
  25 API pages this branch adds
- regenerate tools/api_checker/api_surface.json for develop's API

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/features/object_order.md

@@ -6,7 +6,7 @@ The [JSON standard](https://tools.ietf.org/html/rfc8259.html) defines objects as
 
 The default type `nlohmann::json` uses a `std::map` to store JSON objects, and thus stores object keys **sorted alphabetically**.
 
-??? example
+??? example "Example: `json` sorts object keys"
 
     ```cpp
     #include <iostream>
@@ -39,7 +39,7 @@ The default type `nlohmann::json` uses a `std::map` to store JSON objects, and t
 
 If you do want to preserve the **insertion order**, you can use the type [`nlohmann::ordered_json`](../api/ordered_json.md).
 
-??? example
+??? example "Example: `ordered_json` preserves insertion order"
 
     ```cpp
     --8<-- "examples/ordered_json.cpp"