Fix error in test

tests/baselines/reference/erasableSyntaxOnlyDeclaration.errors.txt

@@ -1,4 +1,3 @@
-esm.d.mts(1,1): error TS1046: Top-level declarations in .d.ts files must start with either a 'declare' or 'export' modifier.
 index.d.ts(1,1): error TS1046: Top-level declarations in .d.ts files must start with either a 'declare' or 'export' modifier.
 
 
@@ -68,9 +67,7 @@ index.d.ts(1,1): error TS1046: Top-level declarations in .d.ts files must start
     export = foo;
 
 
-==== esm.d.mts (1 errors) ====
-    const foo = 1234;
-    ~~~~~
-!!! error TS1046: Top-level declarations in .d.ts files must start with either a 'declare' or 'export' modifier.
+==== esm.d.mts (0 errors) ====
+    declare const foo = 1234;
     export default foo;
 

tests/baselines/reference/erasableSyntaxOnlyDeclaration.symbols

@@ -114,9 +114,9 @@ export = foo;
 
 
 === esm.d.mts ===
-const foo = 1234;
->foo : Symbol(foo, Decl(esm.d.mts, 0, 5))
+declare const foo = 1234;
+>foo : Symbol(foo, Decl(esm.d.mts, 0, 13))
 
 export default foo;
->foo : Symbol(foo, Decl(esm.d.mts, 0, 5))
+>foo : Symbol(foo, Decl(esm.d.mts, 0, 13))
 

tests/baselines/reference/erasableSyntaxOnlyDeclaration.types

@@ -156,7 +156,7 @@ export = foo;
 
 
 === esm.d.mts ===
-const foo = 1234;
+declare const foo = 1234;
 >foo : 1234
 >    : ^^^^
 >1234 : 1234

tests/cases/compiler/erasableSyntaxOnlyDeclaration.ts

@@ -69,5 +69,5 @@ export = foo;
 
 
 // @filename: esm.d.mts
-const foo = 1234;
+declare const foo = 1234;
 export default foo;