[3.12] Correct function name in Doc/extending/embedding.rst (GH-127539) (#130946)

Correct function name in `Doc/extending/embedding.rst` (GH-127539)
(cherry picked from commit e5527f2)

Co-authored-by: Boris Verkhovskiy <[email protected]>

Author: miss-islington

Doc/extending/embedding.rst

@@ -177,8 +177,8 @@ interesting part with respect to embedding Python starts with ::
 
 After initializing the interpreter, the script is loaded using
 :c:func:`PyImport_Import`.  This routine needs a Python string as its argument,
-which is constructed using the :c:func:`PyUnicode_FromString` data conversion
-routine. ::
+which is constructed using the :c:func:`PyUnicode_DecodeFSDefault` data
+conversion routine. ::
 
    pFunc = PyObject_GetAttrString(pModule, argv[2]);
    /* pFunc is a new reference */