add typetraits.OrdinalEnum, enumutils.symbolName (#17281)

lib/pure/typetraits.nim

@@ -15,16 +15,20 @@
 import std/private/since
 export system.`$` # for backward compatibility
 
-type SomeEnumWithHoles* = (not Ordinal) and enum ## Enum with holes.
+type HoleyEnum* = (not Ordinal) and enum ## Enum with holes.
+type OrdinalEnum* = Ordinal and enum ## Enum without holes.
 
 runnableExamples:
   type A = enum a0 = 2, a1 = 4, a2
   type B = enum b0 = 2, b1, b2
-  assert A is SomeEnumWithHoles
-  assert B isnot SomeEnumWithHoles
-  assert int isnot SomeEnumWithHoles
+  assert A is enum
+  assert A is HoleyEnum
+  assert A isnot OrdinalEnum
+  assert B isnot HoleyEnum
+  assert B is OrdinalEnum
+  assert int isnot HoleyEnum
   type C[T] = enum h0 = 2, h1 = 4
-  assert C[float] is SomeEnumWithHoles
+  assert C[float] is HoleyEnum
 
 proc name*(t: typedesc): string {.magic: "TypeTrait".} =
   ## Returns the name of the given type.