Match ABI tag order in namespace tests to abi_macros.hpp

NLOHMANN_JSON_ABI_TAGS concatenates the tags as _diag, _ldvcmp, _dp,
but the default and noversion ABI tests expected _diag, _dp, _ldvcmp.
The tests therefore failed whenever both JSON_DIAGNOSTIC_POSITIONS and
JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON were enabled, a combination
CI never exercises. Reorder the expectations to match the header.

Also document the _dp tag in the namespace feature page, which listed
only _diag and _ldvcmp.

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

docs/mkdocs/docs/features/namespace.md

@@ -15,6 +15,7 @@ The complete default namespace name is derived as follows:
     - [`JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md) defined non-zero appends `_diag`.
     - [`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../api/macros/json_use_legacy_discarded_value_comparison.md)
       defined non-zero appends `_ldvcmp`.
+    - [`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md) defined non-zero appends `_dp`.
 - The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
   underscores. To omit the version component, see [Disabling the version component](#disabling-the-version-component)
   below.

tests/abi/config/default.cpp

@@ -24,14 +24,14 @@ TEST_CASE("default namespace")
         expected += "_diag";
 #endif
 
-#if JSON_DIAGNOSTIC_POSITIONS
-        expected += "_dp";
-#endif
-
 #if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
         expected += "_ldvcmp";
 #endif
 
+#if JSON_DIAGNOSTIC_POSITIONS
+        expected += "_dp";
+#endif
+
         expected += "_v" STRINGIZE(NLOHMANN_JSON_VERSION_MAJOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_MINOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_PATCH) "::basic_json";

tests/abi/config/noversion.cpp

@@ -25,14 +25,14 @@ TEST_CASE("default namespace without version component")
         expected += "_diag";
 #endif
 
-#if JSON_DIAGNOSTIC_POSITIONS
-        expected += "_dp";
-#endif
-
 #if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
         expected += "_ldvcmp";
 #endif
 
+#if JSON_DIAGNOSTIC_POSITIONS
+        expected += "_dp";
+#endif
+
         expected += "::basic_json";
 
         // fallback for Clang