docs: add clarification and add filter in the filters list

docs/filters.rst

@@ -22,6 +22,9 @@ Event Filters
      - Include and exclude keys from the event object
    * - dashes_to_underscores
      - This filter changes the dashes in all keys in the payload to be underscore.
+   * - insert_hosts_to_meta
+     - This filter inserts the hosts from the event into the meta key within the event
+       based on a custom path in the event object.
 
 | Events filters can be chained one after the other, and the updated data is
 | sent from one filter to the next.
@@ -30,7 +33,7 @@ Event Filters
 | When the rulebook starts the Source plugin it associates the correct filters
 | and transforms the data before putting it into the queue.
 
-e.g.
+Examples:
 
 .. code-block:: yaml
 
@@ -45,6 +48,17 @@ e.g.
             exclude_keys: ['*_url', '_links', 'base', 'sender', 'owner', 'user']
         - dashes_to_underscores:
 
+
+.. code-block:: yaml
+
+    sources:
+        - foo.bar.my_custom_source:
+            url: https://my_custom_source.com
+          filters:
+            - ansible.eda.insert_hosts_to_meta:
+                host_path: "alert.meta.instances"
+
+
 | In the above example the data is first passed thru the json_filter and then
 | thru the dashes_to_underscores filter.
 | Keys in the event payload can only contain letters, numbers and underscores.

docs/host_limit.rst

@@ -29,6 +29,12 @@ To accommodate this, the EDA collection provides the `insert_hosts_to_meta` filt
 allowing any plugin to customize the value of `event.meta.hosts` based on the contents
 of a specific key in the event.
 
+.. note::
+
+    The `host_path` in filter `insert_hosts_to_meta` don't expect the `event` root key unlike conditions
+    or action arguments.
+
+
 Example:
 
 .. code-block:: yaml