Update comments in demo project's main forms

Comment containing list of snippets included in the `drive` category
demo was updated to:

* Include two snippets that are demonstrated but were missing from the
list.

* Correct name of `CurentDrive` in snippet list to use "correct"
mis-spelling!

Comment containing list of snippets in `winsys` category demo was
updated to note that one snippet is from `reg` category, rather than
`winsys`.

Author: delphidabbler

tests/Cat-Drive/FmDriveCatDemo.pas

@@ -42,8 +42,10 @@ implementation
 {$R *.dfm}
 
 {
-* CurrentDrive
+* CurentDrive (sic)
   Returns the letter that identifies the current drive.
+* DeleteVolumeName
+  Deletes an existing volume label on a given drive.
 * DiskSpaceInfo
   Gets total and free space information for a drive.
 * DriveDisplayName
@@ -68,6 +70,8 @@ implementation
   Check if a drive number represents a valid drive.
 * ListDrives
   Gets list of the system's drive root paths.
+* SetVolumeName
+  Sets the name of the volume on a given drive.
 * VolumeName
   Returns volume name of a drive.
 }

tests/Cat-WinSys/FmWinSysCatDemo.pas

@@ -48,7 +48,7 @@ implementation
   Returns the Windows common file directory.
 * ComputerName
   Returns the name of the computer.
-* GetCurrentVersionRegStr #
+* GetCurrentVersionRegStr
   Gets a string value from a subkey of the Windows current version registry key.
 * GetRegistryString
   Gets a value from the registry from a specified root and sub key.
@@ -82,6 +82,9 @@ implementation
   Returns the Windows directory.
 * WindowsProductID
   Returns the Windows product ID.
+
+All snippets are from the `winsys` category except GetCurrentVersionRegStr that
+is from the `reg` category.
 }
 
 procedure TWinSysCatDemoForm.btnGCVRSClick(Sender: TObject);