chore: add language identifiers

src/content/docs/apm/agents/python-agent/python-agent-api/insertdistributedtraceheaders-python-agent-api.mdx

@@ -13,7 +13,7 @@ redirects:
 
 ## Syntax
 
-```
+```py
 newrelic.agent.insert_distributed_trace_headers(list_of_headers)
 ```
 
@@ -57,7 +57,7 @@ This call is used to implement distributed tracing. It inserts headers into a li
       </td>
 
       <td>
-        Required. A list of headers. This list will be mutated by the call (headers will be inserted into the list in the form of (header_name, header_value)).
+        Required. A list of headers. This list will be mutated by the call (headers will be inserted into the list in the form of `(header_name, header_value)`).
       </td>
     </tr>
   </tbody>
@@ -77,11 +77,10 @@ Returns `None`. The input list will be updated by a call to this function.
 
 An example of using `insert_distributed_trace_headers` in creating an [external trace](/docs/agents/python-agent/python-agent-api/external-trace) from within single a background task:
 
-```
+```py
 @newrelic.agent.background_task()
 def main(url):
-    with newrelic.agent.ExternalTrace('my_external_library',
-            url, method='GET'):
+    with newrelic.agent.ExternalTrace('my_external_library', url, method='GET'):
         # Generate the payload in the context of the ExternalTrace
         # span that sends it
         headers = []
@@ -95,7 +94,7 @@ def main(url):
 
 An example of using `insert_distributed_trace_headers` in creating an [external trace](/docs/agents/python-agent/python-agent-api/external-trace):
 
-```
+```py
 def _bind_url(url, *args, **kwargs):
     # _bind_url is called with the args and kwargs sent to the `get`
     # method below