replace "ideal" with "untyped"

R=r
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=35242
CL=35258

doc/go_tutorial.txt

@@ -281,7 +281,7 @@ An Interlude about Constants
 
 Although integers come in lots of sizes in Go, integer constants do not.
 There are no constants like "0ll" or "0x0UL".   Instead, integer
-constants are evaluated as ideal, large-precision values that
+constants are evaluated as large-precision values that
 can overflow only when they are assigned to an integer variable with
 too little precision to represent the value.