[GRASS5] New help button - please text review

Hi,

maybe you have seen the new help button in the
startup GUI. I have taken text here and there and
written a small intro:

In CVS:
  grass51/lib/init/helptext.html

Can a native speaker please review?

The help file is opened in the mini HTML browser
which comes with NVIZ. So it should work on
any system.

Markus