fixes requiresInit for var statements without initialization (#24177)

ref https://forum.nim-lang.org/t/12530

tests/objects/trequireinit.nim

@@ -0,0 +1,10 @@
+discard """
+  errormsg: "The MPlayerObj type doesn't have a default value. The following fields must be initialized: foo."
+"""
+
+type
+  MPlayerObj* {.requiresInit.} = object
+    foo: range[5..10] = 5
+
+var a: MPlayerObj
+echo a.foo