NetworkPkg: Change OPTIONAL keyword usage style

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3760

Update all use of ', OPTIONAL' to ' OPTIONAL,' for function params.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>

NetworkPkg/Include/Library/HttpIoLib.h

@@ -234,9 +234,9 @@ HttpIoCreateIo (
 EFI_STATUS
 HttpIoSendRequest (
   IN  HTTP_IO                *HttpIo,
-  IN  EFI_HTTP_REQUEST_DATA  *Request,      OPTIONAL
+  IN  EFI_HTTP_REQUEST_DATA  *Request       OPTIONAL,
   IN  UINTN                  HeaderCount,
-  IN  EFI_HTTP_HEADER        *Headers,      OPTIONAL
+  IN  EFI_HTTP_HEADER        *Headers       OPTIONAL,
   IN  UINTN                  BodyLength,
   IN  VOID                   *Body          OPTIONAL
   );