Update src/compiler.ts

Co-authored-by: Max Graey <[email protected]>

Author: surma

src/compiler.ts

@@ -9943,6 +9943,7 @@ export class Compiler extends DiagnosticEmitter {
       case TypeKind.I31REF: {
         // Needs to be true when the ref is _not_ null.
         // Therefore: 1 - <ref.is_null>
+        // Therefore: !(<ref.is_null>)
         return type.size == 64
           ? module.unary(UnaryOp.EqzI64, module.ref_is(RefIsOp.RefIsNull, expr))
           : module.unary(UnaryOp.EqzI32, module.ref_is(RefIsOp.RefIsNull, expr));