Doc: Update plugin to use nonstandard header (#297) (#298)

(cherry picked from commit 58c16d4)

Co-authored-by: Karen Metts <[email protected]>

Author: mergify[bot]

docs/index.asciidoc

@@ -18,7 +18,7 @@ END - GENERATED VARIABLES, DO NOT EDIT!
 
 === {elastic-integration-name} filter plugin
 
-include::{include_path}/plugin_header.asciidoc[]
+include::{include_path}/plugin_header-nonstandard.asciidoc[]
 
 .Elastic Enterprise License
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