DOCS-15860 full validation does not report index info when collection validation fails (#2631)

* DOCS-15860 full validation does not report index info when collection validation fails

* external review

Author: jmd-mongo

source/reference/command/validate.txt

@@ -203,7 +203,7 @@ Specify :ref:`full: true <cmd-validate-full>` for more detailed output.
 
 .. data:: validate.nIndexes
 
-   The number of indexes on the collection.
+   The number of indexes on the collection that were validated.
 
 .. data:: validate.keysPerIndex