Update pre-filtering notes

in the new vectorSearch index creation, there is no longer dynamic mapping, so both filtering on year would not work as well

docs/7-vector-search/9-filtering.mdx

@@ -8,7 +8,7 @@ One of the nice things about Vector Search in Atlas is its seamless integration
 
 ## Pre-filtering using number fields
 
-If we want to pre-filter all books that are from 2001 we can do:
+If we want to pre-filter all books that are from 2001 we can try this (but it won't work right now):
 
 ```js
 [
@@ -26,7 +26,7 @@ If we want to pre-filter all books that are from 2001 we can do:
 
 ## Pre-filtering using string fields
 
-Strings are a bit more tricky. We can think this will work, but right now it wont:
+We can try this and it won't work as well:
 
 ```js
 [
@@ -44,7 +44,7 @@ Strings are a bit more tricky. We can think this will work, but right now it won
 
 The problem lies on the `vectorsearch` index, not in this code. For String fields to be pre-filtered we need to add a mapping to those fields in our Search Index definition. To do that, go to MongoDB Atlas, go to your collections and open again the Search Indexes tab, as you did while [creating the indexes](/docs/vector-search/create-index)
 
-In this case, we already have our index and we're going to edit it in the JSON editor. Just change the index adding a mapping for the `language` field. The index should look like:
+In this case, we already have our index and we're going to edit it in the JSON editor. Just change the index adding a mapping for the `year` field and `language` field. The index should look like:
 
 ```js
 {
@@ -55,6 +55,10 @@ In this case, we already have our index and we're going to edit it in the JSON e
       "numDimensions": 1536,
       "similarity": "cosine"
     },
+    {
+      "type": "filter",
+      "path": "year"
+    },
     {
       "type": "filter",
       "path": "language"
@@ -63,9 +67,13 @@ In this case, we already have our index and we're going to edit it in the JSON e
 }
 ```
 
-The only difference is that we've added this part, stating that `language` should be indexed as a [filter](https://www.mongodb.com/docs/atlas/atlas-vector-search/vector-search-type/#about-the-filter-type).
+The only difference is that we've added this part, stating that `year` and `language` should be indexed as a [filter](https://www.mongodb.com/docs/atlas/atlas-vector-search/vector-search-type/#about-the-filter-type).
 
 ```js
+    {
+      "type": "filter",
+      "path": "year"
+    },
     {
       "type": "filter",
       "path": "language"