Fixed typo

As a part of PR review suggestions

Co-authored-by: Thomas Kriechbaumer <[email protected]>

Author: cdeler

src/h2/utilities.py

@@ -609,7 +609,7 @@ def _split_outbound_cookie_fields(headers, hdr_validation_flags):
     to split the Cookie header field into separate header fields
 
     We want to do it for outbound requests, as we are doing for
-    inbound
+    inbound.
     """
     for header in headers:
         if header[0] in (b'cookie', 'cookie'):