website: fix docs for vmware esxi discrep [GH-674]

website/source/docs/builders/vmware.html.markdown

@@ -87,7 +87,8 @@ Optional:
   The default is "1", which corresponds to a growable virtual disk split in
   2GB files.  This option is for advanced usage, modify only if you
   know what you're doing.  For more information, please consult the
-  [Virtual Disk Manager User's Guide](http://www.vmware.com/pdf/VirtualDiskManager.pdf).
+  [Virtual Disk Manager User's Guide](http://www.vmware.com/pdf/VirtualDiskManager.pdf)
+  for desktop VMware clients. For ESXi, refer to the proper ESXi documentation.
 
 * `floppy_files` (array of strings) - A list of files to put onto a floppy
   disk that is attached when the VM is booted for the first time. This is