Fix JQ command for processing mapping.json (#3830)

Updated command to process mapping.json output with JQ.

Author: octavioranieri

troubleshoot/elasticsearch/mapping-explosion.md

@@ -50,7 +50,7 @@ To confirm the field totals of an index to check for mapping explosion:
 * If you’re inclined to use the [third-party tool JQ](https://stedolan.github.io/jq), you can process the [get mapping](../../manage-data/data-store/mapping.md) `mapping.json` output.
 
     ```sh
-    $ cat mapping.json | jq -c 'to_entries[]| .key as $index| [.value.mappings| to_entries[]|select(.key=="properties") | {(.key):([.value|..|.type?|select(.!=null)]|length)}]| map(to_entries)| flatten| from_entries| ([to_entries[].value]|add)| {index: $index, field_count: .}'
+    cat mapping.json | jq -c 'to_entries[]| .key as $index| [.value.mappings| to_entries[]|select(.key=="properties") | {(.key):([.value|..|.type?|select(.!=null)]|length)}]| map(to_entries)| flatten| from_entries| ([to_entries[].value]|add)| {index: $index, field_count: .}'
     ```