suppress deprecated warnings (nim-lang#19408)

* suppress deprecated warnings

once bump version to 1.7.3 enable deprecated messages

* deprecate later

Author: ringabout

lib/system.nim

@@ -213,8 +213,7 @@ proc `addr`*[T](x: T): ptr T {.magic: "Addr", noSideEffect.} =
   ##  echo p[]    # b
   discard
 
-proc unsafeAddr*[T](x: T): ptr T {.magic: "Addr", noSideEffect,
-  deprecated: "'unsafeAddr' is a deprecated alias for 'addr'".} =
+proc unsafeAddr*[T](x: T): ptr T {.magic: "Addr", noSideEffect.} =
   ## Builtin `addr` operator for taking the address of a memory
   ## location.
   ##