change incorrect comment

src/parser.ts

@@ -36,7 +36,7 @@ export class IndexFileEntry {
   async parse(): Promise<Metafile> {
     if (this.metafile === false) {
       throw new Error(
-        "Cannot parse non-metafiles! Use `file.readText()` instead to get the file contents.",
+        "Cannot parse non-metafiles! Use `file.fetchContents()` instead to get the file contents.",
       );
     }
     const fileContent = await this.file.fetchContents();