update docs

Author: GrantBirki

docs/configuration.md

@@ -95,6 +95,12 @@ When set to `true`, enables a catch-all route that will handle requests to unkno
 **Default:** `false`  
 **Example:** `false`
 
+### `normalize_headers`
+
+When set to `true`, normalizes incoming HTTP headers by lowercasing and trimming them. This ensures consistency in header names and values.
+
+**Default:** `true`  
+
 ## Endpoint Options
 
 ### `path`

docs/handler_plugins.md

@@ -67,7 +67,7 @@ By default, the headers are normalized (lowercased and trimmed) but kept as stri
 
 For example, if the client sends the following headers:
 
-```
+```text
 Host: hooks.example.com
 User-Agent: foo-client/1.0
 Accept: application/json, text/plain, */*