update ignore_annotations/labels doc to include context for regexp …

…in nested metadata objects (#2454)

* add note about regexp and nested metadata objects

* Update website/docs/index.html.markdown

Co-authored-by: Alex Somesan <alex.somesan@gmail.com>

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Co-authored-by: Alex Somesan <alex.somesan@gmail.com>

website/docs/index.html.markdown

@@ -142,6 +142,8 @@ In certain cases, external systems can add and modify resources annotations and
 
 Both attributes support RegExp to match metadata objects more effectively.
 
+~> **Note:** RegExp will only work on root metadata objects. It's currently not possible to use RegExp for ignoring annotations/labels in metadata objects that are nested such as `spec.template.metadata[0].annotations["..."]`.
+
 Please keep in mind that all data sources remain unaffected, and the provider always returns all labels and annotations, despite the `ignore_annotations` and `ignore_labels` settings. The same applies to the pod and job definitions that fall under templates. To ignore certain annotations and/or labels on the template level, please use the `ignore_changes` feature of the [lifecycle](https://developer.hashicorp.com/terraform/language/meta-arguments/lifecycle) meta-argument.
 
 ### Examples