Revert "try without using the sized aliases"

This reverts commit 6c30a84.

Author: Mathieu Scheltienne

nibabel/casting.py

@@ -25,10 +25,10 @@ class CastingError(Exception):
 
 # np.sctypes is deprecated in numpy 2.0 and np.core.sctypes should not be used instead.
 sctypes = {
-    'int': list(set([np.byte, np.short, np.intc, np.longlong])),
-    'uint': list(set([np.ubyte, np.ushort, np.uintc, np.ulonglong])),
-    'float': list(set([np.half, np.single, np.double, np.longdouble])),
-    'complex': list(set([np.csingle, np.cdouble, np.clongdouble])),
+    'int': [np.int8, np.int16, np.int32, np.int64],
+    'uint': [np.uint8, np.uint16, np.uint32, np.uint64],
+    'float': [np.float16, np.float32, np.float64, np.float128],
+    'complex': [np.complex64, np.complex128, np.complex256],
     'others': [bool, object, bytes, str, np.void],
 }