cue: define all Op constant values explicitly with that type

Follow-up to fca61f5.

go doc (somewhat understandably) fails to see constant values of type
Op unless they are explicitly defined to be of that type, even though
Op is defined as an alias of adt.Op and the values assigned to those
constants are of the type adt.Op.

Updates #1374

Signed-off-by: Paul Jolly <paul@myitcv.io>
Change-Id: Ie07c64c5de1c866bc774a0c2e5dbcd08e61e6f9b
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/527238
Unity-Result: CUEcueckoo <cueckoo@cuelang.org>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>

Author: myitcv

cue/op.go

@@ -25,40 +25,40 @@ type Op = adt.Op
 
 // Values of Op.
 const (
-	NoOp = adt.NoOp
-
-	AndOp = adt.AndOp
-	OrOp  = adt.OrOp
-
-	SelectorOp = adt.SelectorOp
-	IndexOp    = adt.IndexOp
-	SliceOp    = adt.SliceOp
-	CallOp     = adt.CallOp
-
-	BooleanAndOp = adt.BoolAndOp
-	BooleanOrOp  = adt.BoolOrOp
-
-	EqualOp            = adt.EqualOp
-	NotOp              = adt.NotOp
-	NotEqualOp         = adt.NotEqualOp
-	LessThanOp         = adt.LessThanOp
-	LessThanEqualOp    = adt.LessEqualOp
-	GreaterThanOp      = adt.GreaterThanOp
-	GreaterThanEqualOp = adt.GreaterEqualOp
-
-	RegexMatchOp    = adt.MatchOp
-	NotRegexMatchOp = adt.NotMatchOp
-
-	AddOp           = adt.AddOp
-	SubtractOp      = adt.SubtractOp
-	MultiplyOp      = adt.MultiplyOp
-	FloatQuotientOp = adt.FloatQuotientOp
-	IntQuotientOp   = adt.IntQuotientOp
-	IntRemainderOp  = adt.IntRemainderOp
-	IntDivideOp     = adt.IntDivideOp
-	IntModuloOp     = adt.IntModuloOp
-
-	InterpolationOp = adt.InterpolationOp
+	NoOp Op = adt.NoOp
+
+	AndOp Op = adt.AndOp
+	OrOp  Op = adt.OrOp
+
+	SelectorOp Op = adt.SelectorOp
+	IndexOp    Op = adt.IndexOp
+	SliceOp    Op = adt.SliceOp
+	CallOp     Op = adt.CallOp
+
+	BooleanAndOp Op = adt.BoolAndOp
+	BooleanOrOp  Op = adt.BoolOrOp
+
+	EqualOp            Op = adt.EqualOp
+	NotOp              Op = adt.NotOp
+	NotEqualOp         Op = adt.NotEqualOp
+	LessThanOp         Op = adt.LessThanOp
+	LessThanEqualOp    Op = adt.LessEqualOp
+	GreaterThanOp      Op = adt.GreaterThanOp
+	GreaterThanEqualOp Op = adt.GreaterEqualOp
+
+	RegexMatchOp    Op = adt.MatchOp
+	NotRegexMatchOp Op = adt.NotMatchOp
+
+	AddOp           Op = adt.AddOp
+	SubtractOp      Op = adt.SubtractOp
+	MultiplyOp      Op = adt.MultiplyOp
+	FloatQuotientOp Op = adt.FloatQuotientOp
+	IntQuotientOp   Op = adt.IntQuotientOp
+	IntRemainderOp  Op = adt.IntRemainderOp
+	IntDivideOp     Op = adt.IntDivideOp
+	IntModuloOp     Op = adt.IntModuloOp
+
+	InterpolationOp Op = adt.InterpolationOp
 )
 
 // isCmp reports whether an op is a comparator.