Editorial: Define 4 SDOs on empty Script (tc39#2406)

Specifically:
- LexicallyDeclaredNames
- LexicallyScopedDeclarations
- VarDeclaredNames
- VarScopedDeclarations

Fixes tc39#2354.

Author: jmdyck

spec.html

@@ -7393,6 +7393,10 @@ <h1>Static Semantics: LexicallyDeclaredNames</h1>
       <emu-alg>
         1. Return a new empty List.
       </emu-alg>
+      <emu-grammar>Script : [empty]</emu-grammar>
+      <emu-alg>
+        1. Return a new empty List.
+      </emu-alg>
       <emu-grammar>ScriptBody : StatementList</emu-grammar>
       <emu-alg>
         1. Return TopLevelLexicallyDeclaredNames of |StatementList|.
@@ -7511,6 +7515,10 @@ <h1>Static Semantics: LexicallyScopedDeclarations</h1>
       <emu-alg>
         1. Return a new empty List.
       </emu-alg>
+      <emu-grammar>Script : [empty]</emu-grammar>
+      <emu-alg>
+        1. Return a new empty List.
+      </emu-alg>
       <emu-grammar>ScriptBody : StatementList</emu-grammar>
       <emu-alg>
         1. Return TopLevelLexicallyScopedDeclarations of |StatementList|.
@@ -7741,6 +7749,10 @@ <h1>Static Semantics: VarDeclaredNames</h1>
       <emu-alg>
         1. Return a new empty List.
       </emu-alg>
+      <emu-grammar>Script : [empty]</emu-grammar>
+      <emu-alg>
+        1. Return a new empty List.
+      </emu-alg>
       <emu-grammar>ScriptBody : StatementList</emu-grammar>
       <emu-alg>
         1. Return TopLevelVarDeclaredNames of |StatementList|.
@@ -7956,6 +7968,10 @@ <h1>Static Semantics: VarScopedDeclarations</h1>
       <emu-alg>
         1. Return a new empty List.
       </emu-alg>
+      <emu-grammar>Script : [empty]</emu-grammar>
+      <emu-alg>
+        1. Return a new empty List.
+      </emu-alg>
       <emu-grammar>ScriptBody : StatementList</emu-grammar>
       <emu-alg>
         1. Return TopLevelVarScopedDeclarations of |StatementList|.