Update docs/en/latest/plugins/opentelemetry.md

Co-authored-by: Peter Zhu <starszcan@gmail.com>

docs/en/latest/plugins/opentelemetry.md

@@ -47,7 +47,7 @@ The Plugin only supports binary-encoded [OLTP over HTTP](https://opentelemetry.i
 | additional_attributes                 | array[string] | False    |                                                 |                                                              | Variables and its values which will be appended to the trace span.                                                                                                                                                                           |
 | additional_attributes[0]              | string        | True     |                                                 |                                                              | APISIX or Nginx variables. For example, `http_header` or `route_id`.                                                                                                                                                                         |
 | additional_header_attributes          | array[string] | False    |                                                 |                                                              | Variables and its values which will be appended to the trace span.                                                                                                                                                                           |
-| additional_header_attributes[0]       | string        | True     |                                                 |                                                              | Request headers. For example, `x-my-header"` or `x-my-headers-*` to include all headers with the prefix `x-my-headers-`.                                                                                                                                                                         |
+| additional_header_attributes[0]       | string        | True     |                                                 |                                                              | Request headers. For example, `x-my-header` or `x-my-headers-*` to include all headers with the prefix `x-my-headers-`.                                                                                                                                                                         |
 
 ### Configuring the collector