Add Value alias to Preserve[void]

src/preserves.nim

@@ -9,6 +9,8 @@ import ./preserves/private/[encoding, decoding, dot, macros, parsing, texts, val
 
 export encoding, decoding, parsing, texts, values
 
+type Value* = Preserve[void]
+
 when defined(tracePreserves):
   when defined(posix):
     template trace(args: varargs[untyped]) = {.cast(noSideEffect).}: stderr.writeLine(args)