[stdlib][socket] import constants from the _socket module

Add missing imports.
docs:
https://docs.python.org/dev/library/socket.html

Author: guoci

stdlib/socket.pyi

@@ -969,6 +969,33 @@ if sys.platform != "linux":
 if sys.platform != "darwin" and sys.platform != "linux":
     __all__ += ["AF_BLUETOOTH"]
 
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
+    from _socket import (
+        BTPROTO_HCI as BTPROTO_HCI,
+        BTPROTO_L2CAP as BTPROTO_L2CAP,
+        BTPROTO_SCO as BTPROTO_SCO,
+    )
+
+    __all__ += ["BTPROTO_HCI", "BTPROTO_L2CAP", "BTPROTO_SCO"]
+
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
+    from _socket import (
+        HCI_FILTER as HCI_FILTER,
+        HCI_TIME_STAMP as HCI_TIME_STAMP,
+        HCI_DATA_DIR as HCI_DATA_DIR,
+    )
+
+    __all__ += ["HCI_FILTER", "HCI_TIME_STAMP", "HCI_DATA_DIR"]
+
+if sys.version_info >= (3, 11) and sys.platform != "linux" and sys.platform != "win32" and sys.platform != "darwin":
+    from _socket import (
+        SCM_CREDS2 as SCM_CREDS2,
+        LOCAL_CREDS as LOCAL_CREDS,
+        LOCAL_CREDS_PERSISTENT as LOCAL_CREDS_PERSISTENT,
+    )
+
+    __all__ += ["SCM_CREDS2", "LOCAL_CREDS", "LOCAL_CREDS_PERSISTENT"]
+
 if sys.platform == "win32" and sys.version_info >= (3, 12):
     __all__ += ["AF_HYPERV"]