bug#35579: Add example of setting view-exit-action to a "function with one argument"

[Noam Postavsky]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

>    view-exit-action is a variable defined in ‘view.el’.
>    Its value is nil
>
>      Automatically becomes buffer-local when set.
>
>    Documentation:
>    If non-nil, a function with one argument (a buffer) called when finished 
> viewing.
>
> Better add an example of how to set "a function with one argument". Thanks.

I don't see why we should add an example of how to use setq or customize
in an otherwise unrelated docstring.  Or did you mean an example of how
to write a function with one argument?  I'd say that belongs in the
elisp manual.