bug#48504: Improve style of C-h t description (Preface)

[Sebastian Urban]

> > Currently, in the Preface of the Emacs manual (EMACS.TEXI - L1291),
> > there is:
> >     To run the tutorial, start Emacs and type @kbd{C-h t} (which is
> >     ``control h and then t'').
> >
> > I think, the part between parens should look better, e.g. similar to
> > this part of SCREEN.TEXI (L126):
> >     ...(hold down @key{Ctrl} and type @kbd{x}, then let go of
> >     @key{Ctrl} and type @kbd{=})...
> > ...i.e.:
> >     ...(hold down @key{Ctrl} and type @kbd{h}, then let go of
> >     @key{Ctrl} and type @kbd{t}).
>
> We didn't yet introduce the Ctrl etc. notation at that place.

What about "Control" instead of "Ctrl"?