WIP [NEW] Change NbtName repsentation from compound nesting

Simplify naming code by switching away from single-entry-compound code
with verification.

SNBT now doesn't print root name since it's an unnamed variant, which
matches the behavior of Minecraft Java's net.minecraft.data.Main
NBT -> SNBT data generator tool with the --dev flag.

src/commonTest/kotlin/test/verify/VerifyingNbtWriter.kt

@@ -25,7 +25,7 @@ internal class VerifyingNbtWriter(
     override fun beginRootTag(type: NbtTagType, name: String): Unit = transitionState(::beginRootTag) {
         assertStateIs<State.InRoot>(state)
         assertWrittenRootTypeEquals(tag.value.type, type)
-        // TODO Check name (named AND unnamed variants)
+        assertWrittenRootNameEquals(tag.name, name)
 
         Unit to State.AwaitingValue(tag.value, State.Complete)
     }
@@ -258,6 +258,10 @@ internal class VerifyingNbtWriter(
             assertEquals(expected, actual, messagePrefix + "Incorrect root type was written")
         }
 
+        fun assertWrittenRootNameEquals(expected: String, actual: String) {
+            assertEquals(expected, actual, messagePrefix + "Incorrect root name was written")
+        }
+
         inline fun <reified T : NbtTag> assertWrittenTagTypeEquals(expected: NbtTag, actual: KClass<T>) {
             contract { returns() implies (expected is T) }