refactor: use function signature

Author: velut

src/package-overview.ts

@@ -1,9 +1,9 @@
 import { SourceFile, SyntaxKind } from "ts-morph";
 
-export const packageOverview = (indexFile: SourceFile): string | undefined => {
+export function packageOverview(indexFile: SourceFile): string | undefined {
 	return indexFile
 		.getDescendantsOfKind(SyntaxKind.JSDocTag)
 		.find((tag) => tag.getTagName() === "packageDocumentation")
 		?.getParentIfKind(SyntaxKind.JSDoc)
 		?.getText();
-};
+}