added more tests and updated the changelog

changelog.md

@@ -71,6 +71,9 @@ iterator mypairs[T](x: openarray[T]): tuple[idx: int, val: lent T]
 
 ## Language changes
 
+- `uint64` is now finally a regular ordinal type. This means `high(uint64)` compiles
+  and yields the correct value.
+
 
 ### Tool changes
 

tests/misc/tlowhigh.nim

@@ -1,5 +1,12 @@
 discard """
     action: run
+    output: '''
+18446744073709551615
+9223372036854775807
+4294967295
+0
+0
+'''
 """
 
 var x: range[-1'f32..1'f32]
@@ -16,3 +23,10 @@ doAssert y.type.high == 1'f64
 # bug #11972
 var num: uint8
 doAssert num.high.float == 255.0
+
+echo high(uint64)
+echo high(int64)
+echo high(uint32)
+
+echo low(uint64)
+echo low(uint32)