Update spec.bs

spec.bs

@@ -2668,7 +2668,8 @@ is a [=structured header=] whose value must be an [=structured header/integer=].
 
 <div algorithm>
 To <dfn>fetch trusted signals</dfn> given a [=URL=] |url|, an [=origin=] |scriptOrigin|, a
-[=policy container=] |policyContainer|, and a [=boolean=] |isBiddingSignal|:
+[=policy container=] |policyContainer|, and a [=boolean=] |isBiddingSignal|, and returning
+a [=tuple=] (an [=ordered map=], [=ordered map=], [=Number=]):
 
   1. Let |request| be a new [=request=] with the following properties:
     :   [=request/URL=]
@@ -2714,19 +2715,19 @@ To <dfn>fetch trusted signals</dfn> given a [=URL=] |url|, an [=origin=] |script
       [:X-fledge-bidding-signals-format-version:] and "`item`" from |headers|.
     1. Set |signals| to the result of [=parsing JSON bytes to an Infra value=] |responseBody|.
   1. Wait for |signals| to be set.
-  1. If |signals| is a parsing exception, or if |signals| is not an [=ordered map=], return « null,
-    null, null ».
+  1. If |signals| is a parsing exception, or if |signals| is not an [=ordered map=], return a
+    [=tuple=] (null, null, null).
   1. If |formatVersion| is 2:
-    1. If |signals|["`keys`"] does not [=map/exist=], return « null, null, null ».
+    1. If |signals|["`keys`"] does not [=map/exist=], [=tuple=] (null, null, null ).
     1. Set |signals| to |signals|["`keys`"].
-    1. If |signals| is not an [=ordered map=], return « null, null, null ».
+    1. If |signals| is not an [=ordered map=], return a [=tuple=] (null, null, null).
     1. If |signals|["`perInterestGroupData`"] [=map/exists=] and is an [=ordered map=]:
       1. [=Assert=] |isBiddingSignal| is true.
       1. Let |perInterestGroupData| be |signals|["`perInterestGroupData`"].
   1. [=map/For each=] |key| → |value| of |signals|:
     1. [=map/Set=] |signals|[|key|] to the result of [=serializing an Infra value to a JSON string=]
       given |value|.
-  1. Return « |signals|, |perInterestGroupData|, |dataVersion| ».
+  1. Return a [=tuple=] (|signals|, |perInterestGroupData|, |dataVersion|).
 </div>
 
 <div algorithm>