fix variable name booksFrom1985WithMoreThan150pages

Author: wenjie-mdb

docs/30-simple-queries/6-writing-long-pipelines.mdx

@@ -62,7 +62,7 @@ let showOnlyTheseFields = {$project: {_id: 0, title: 1, year: 1, totalInventory:
 let getJust15books =  {$limit: 15};
 
 db.books.aggregate([
-    booksFrom1985With150pages,
+    booksFrom1985WithMoreThan150pages,
     showOnlyTheseFields,
     getJust15books,
 ]);