refactor: make isUniqueSymbolDeclaration internal (remove unused export)

Author: Akshit222

src/compiler/emitter.ts

@@ -432,7 +432,7 @@ import * as performance from "./_namespaces/ts.performance.js";
 const brackets = createBracketsMap();
 
 /** @internal */
-export function isUniqueSymbolDeclaration(node: VariableDeclarationList, checker: TypeChecker): boolean {
+function isUniqueSymbolDeclaration(node: VariableDeclarationList, checker: TypeChecker): boolean {
     return node.declarations.some((decl: VariableDeclaration) => {
         // 1. If type is explicitly written, handle as before
         const typeNode: TypeNode | undefined = decl.type;