Wrong spelling of \vboxsvr on help strings

[sylvaticus]

On same help strings of virtualbox "\vboxsvr" is mispelled in "\vboxsrv", confusing users that want mount guest folders from Windows.

Example: open Shared Folder icon on right-bottom of virtual machine windows, select a virtual folder and select "What is this?".

The same in the help-text under the relevant sector of proprieties.

[Frank Mehnert]

The spellings should be consistent but indeed, both spellings are valid.