Update plugins/hwp-previews/README.md

Author: ahuseyn

plugins/hwp-previews/README.md

@@ -156,7 +156,7 @@ This out-of-the-box configuration allows your existing preview workflow to conti
 
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-### Actions & Filters
+## Actions & Filters
 
 See the [Actions & Filters documentation](ACTIONS_AND_FILTERS.md) for a comprehensive list of available hooks and how to use them.