pythongh-99925: Fix inconsistency in json.dumps() error messages

Author: fnesveda

Misc/NEWS.d/next/Library/2022-12-01-15-26-42.gh-issue-99925.vXya8e.rst

@@ -0,0 +1,2 @@
+Unify error messages in :meth:`json.dumps(float('nan'), allow_nan=False)`
+between `indent=None` and `indent=<SOMETHING>`

Modules/_json.c

@@ -1319,9 +1319,10 @@ encoder_encode_float(PyEncoderObject *s, PyObject *obj)
     double i = PyFloat_AS_DOUBLE(obj);
     if (!Py_IS_FINITE(i)) {
         if (!s->allow_nan) {
-            PyErr_SetString(
+            PyErr_Format(
                     PyExc_ValueError,
-                    "Out of range float values are not JSON compliant"
+                    "Out of range float values are not JSON compliant: %s",
+                    PyOS_double_to_string(i, 'r', 0, 0, NULL)
                     );
             return NULL;
         }