test removing dollar for objects out of system (#20242)

* test removing dollar for objects out of system

* test & fixes

* fix bootstrap

* use nimPreviewSlimSystem, test stdlib category

* fix test

lib/std/objectdollar.nim

@@ -0,0 +1,11 @@
+import std/private/miscdollars
+
+proc `$`*[T: object](x: T): string =
+  ## Generic `$` operator for objects with similar output to
+  ## `$` for named tuples.
+  runnableExamples:
+    type Foo = object
+      a, b: int
+    let x = Foo(a: 23, b: 45)
+    assert $x == "(a: 23, b: 45)"
+  tupleObjectDollar(result, x)