ShellPkg: 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: Ray Ni <ray.ni@intel.com>

ShellPkg/Library/UefiShellDebug1CommandsLib/Mm.c

@@ -68,8 +68,8 @@ ShellMmDecodePciAddress (
   IN UINT64                 Address,
   OUT UINT32                *Segment,
   OUT UINT8                 *Bus,
-  OUT UINT8                 *Device,   OPTIONAL
-  OUT UINT8                 *Function, OPTIONAL
+  OUT UINT8                 *Device    OPTIONAL,
+  OUT UINT8                 *Function  OPTIONAL,
   OUT UINT32                *Register  OPTIONAL
   )
 {