add specific check for @deprecated tag in router files

Signed-off-by: patroswastik <swastik12345@hotmail.com>

packages/repo-tools/src/commands/lint-legacy-backend-exports/lint-legacy-backend-exports.ts

@@ -46,10 +46,15 @@ function verifyIndex(pkg: string, packageJson?: BackstagePackageJson) {
   console.log(`Verifying ${pkg}`);
   const tsPath = path.join(pkg, 'src/index.ts');
   const sourceFile = project.getSourceFile(tsPath);
+
+  const tsRouterPath = path.join(pkg, 'src/service/router.ts');
+  const routerFile = project.getSourceFile(tsRouterPath);
+
   if (!sourceFile) {
     console.log(`Could not find ${tsPath}`);
     process.exit(1);
   }
+
   const symbols = sourceFile?.getExportSymbols();
 
   const exportCount = symbols?.length || 0;
@@ -75,9 +80,23 @@ function verifyIndex(pkg: string, packageJson?: BackstagePackageJson) {
       .find(tag => tag.getName() === 'deprecated');
   }
 
+  let routerCreateRouterDeprecated = undefined;
+  if (routerFile) {
+    const routerSymbols = routerFile?.getExportSymbols();
+    const routerCreateRouterExport = routerSymbols?.find(
+      symbol => symbol.getName() === 'createRouter',
+    );
+
+    if (routerCreateRouterExport) {
+      routerCreateRouterDeprecated = routerCreateRouterExport
+        .getJsDocTags()
+        .find(tag => tag.getName() === 'deprecated');
+    }
+  }
+
   if (createRouterExport) {
     console.log('   ❌ createRouter is exported');
-    if (!createRouterDeprecated)
+    if (!createRouterDeprecated && !routerCreateRouterDeprecated)
       console.log('   ❌ createRouter is NOT deprecated');
   }