MdeModulePkg: Add missing PCD usage information in UNI and DEC files.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18081 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/MdeModulePkg.dec

@@ -938,11 +938,13 @@
   
   ## This PCD points to the file name GUID of the BootManagerMenuApp
   #  Platform can customize the PCD to point to different application for Boot Manager Menu
+  # @Prompt Boot Manager Menu File
   gEfiMdeModulePkgTokenSpaceGuid.PcdBootManagerMenuFile|{ 0xdc, 0x5b, 0xc2, 0xee, 0xf2, 0x67, 0x95, 0x4d, 0xb1, 0xd5, 0xf8, 0x1b, 0x20, 0x39, 0xd1, 0x1d }|VOID*|0x0001006b
 
   ## This PCD points to the formset GUID of the driver health management form
   #  The form will be popped up by BDS core when there are Configuration Required driver health intances.
   #  Platform can customize the PCD to point to different formset.
+  # @Prompt Driver Health Management Form
   gEfiMdeModulePkgTokenSpaceGuid.PcdDriverHealthConfigureForm|{ 0xf4, 0xd9, 0x96, 0x42, 0xfc, 0xf6, 0xde, 0x4d, 0x86, 0x85, 0x8c, 0xe2, 0xd7, 0x9d, 0x90, 0xf0 }|VOID*|0x0001006c
 
   ## The number of bytes between registers in serial device.  The default is 1 byte.
@@ -1000,6 +1002,7 @@
 
   ## This PCD points to the front page formset GUID
   #  Compare the FormsetGuid or ClassGuid with this PCD value can detect whether in front page
+  # @Prompt Front Page Formset.
   gEfiMdeModulePkgTokenSpaceGuid.PcdFrontPageFormSetGuid|{ 0xbc, 0x30, 0x0c, 0x9e,0x06, 0x3f, 0xa6, 0x4b, 0x82, 0x88, 0x9, 0x17, 0x9b, 0x85, 0x5d, 0xbe }|VOID*|0x0001006e
 
   ## Base address of the NV variable range in flash device.