Copy String context handling to js overload resolution algorithm

Author: lukewarlow

index.bs

@@ -11151,8 +11151,15 @@ Note: The HTML Standard defines how the validation is performed. [[!HTML]]
             1.  If the argument at index |i| is declared with a [=optional argument/default value=],
                 then append to |values| that default value.
             1.  Otherwise, append to |values| the special value “missing”.
-        1.  Otherwise, append to |values| the result of [=converted to an IDL value|converting=]
-            |V| to IDL type |type|.
+        1. Otherwise:
+            1.  If |type| is an IDL type [=extended attribute associated with|associated with=] the
+                [{{StringContext}}] extended attribute, then set |V| to the result of [=validate the string in context=], passing
+                [=this=], |V|, the {{StringContext}} extended attribute [=identifier=], and the [=identifier=]
+                of the [{{StringContext}}] extended attribute [=related construct=].
+
+                Note: That algorithm may [=JavaScript/throw=] a <l spec=ecmascript>{{TypeError}}</l>.
+            1.  Append to |values| the result of [=converted to an IDL value|converting=]
+                |V| to IDL type |type|.
         1.  Set |i| to |i| + 1.
     1.  If |i| = |d|, then:
         1.  Let |V| be |args|[|i|].
@@ -11351,8 +11358,15 @@ Note: The HTML Standard defines how the validation is performed. [[!HTML]]
             1.  If the argument at index |i| is declared with a [=optional argument/default value=],
                 then append to |values| that default value.
             1.  Otherwise, append to |values| the special value “missing”.
-        1.  Otherwise, append to |values| the result of
-            [=converted to an IDL value|converting=] |V| to IDL type |type|.
+        1. Otherwise:
+            1.  If |type| is an IDL type [=extended attribute associated with|associated with=] the
+                [{{StringContext}}] extended attribute, then set |V| to the result of [=validate the string in context=], passing
+                [=this=], |V|, the {{StringContext}} extended attribute [=identifier=], and the [=identifier=]
+                of the [{{StringContext}}] extended attribute [=related construct=].
+
+                Note: That algorithm may [=JavaScript/throw=] a <l spec=ecmascript>{{TypeError}}</l>.
+            1.  Append to |values| the result of [=converted to an IDL value|converting=]
+                |V| to IDL type |type|.
         1.  Set |i| to |i| + 1.
     1.  While |i| is less than the number of arguments |callable| is declared to take:
         1.  If |callable|'s argument at index |i| is declared with a [=optional argument/default value=],