fix yaml typo build error

Author: kay-kim

source/includes/apiargs-pipeline-geoNear-field.yaml

@@ -181,7 +181,7 @@ description: |
    for a ``2d`` index to use. If a ``2d`` index does not exists, then
    MongoDB looks for a ``2dsphere`` index to use.
 
-  .. versionadded:: 4.0
+   .. versionadded:: 4.0
 
 optional: true
 ...