Change early error for modifiers

spec.html

@@ -35921,7 +35921,7 @@ <h1>Static Semantics: Early Errors</h1>
         <emu-grammar>Atom :: `(?` RegularExpressionModifiers `-` RegularExpressionModifiers `:` Disjunction `)`</emu-grammar>
         <ul>
           <li>
-            It is a Syntax Error if the source text matched by the first |RegularExpressionModifiers| and the source text matched by the second |RegularExpressionModifiers| are both empty.
+            It is a Syntax Error if the source text matched by the second |RegularExpressionModifiers| is empty.
           </li>
           <li>
             It is a Syntax Error if the source text matched by the first |RegularExpressionModifiers| contains the same code point more than once.