info: prev-line and scroll-backward are buggy on gnuplot.info

[Vincent Lefevre]

[Cc to the Debian bug 989029, which I reported last year:

  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=989029

I'm now reporting it upstream since it still occurs with "info"
from Texinfo 7.0.]

The info manual says:

<DEL> ('scroll-backward')
<PREVIOUS>
     Shift the text in this window down.  The inverse of
     'scroll-forward'.  If you are at the start of a node, <DEL> takes
     you to the "previous" node, so that you can read an entire manual
     from finish to start by repeating <DEL>.  The default scroll size
     can be changed by invoking the
     ('scroll-backward-page-only-set-window') command with a numeric
     argument.
[...]

But at least with info from Texinfo 6.7 to 7.0, this doesn't behave
like that in the gnuplot manual, e.g. /usr/share/info/gnuplot.info.gz
from the gnuplot-doc 5.4.4+dfsg1-2 Debian package. Its master menu
contains:

* gnuplot::
* plotting_styles::
* Commands::
* Terminal_types::
* Bugs::
* Concept_Index::
* Command_Index::
* Options_Index::
* Function_Index::
* Terminal_Index::

Go to "Bugs". This gives

------------------------------------------------------------------------
Next: Concept_Index,  Prev: Terminal_types,  Up: Top

5 Bugs
******

Please e-mail bug reports to the gnuplot-bugs mailing list or upload the
report to the gnuplot web site on SourceForge.  Please give complete
information on the version of gnuplot you are using and, if possible, a
test script that demonstrates the bug.  See 'seeking-assistance'.

* Menu:

* known_limitations::
* External_libraries::
------------------------------------------------------------------------

Then do a scroll-backward (with the Backspace or PageUp key) or a
prev-line (with the up arrow key). This gives:

------------------------------------------------------------------------
5.2 External libraries
======================
[...]
------------------------------------------------------------------------

instead of going to Terminal_types.

Going to the previous node gives successively:

5 Bugs
5.2 External libraries
5.1 known limitations
5 Bugs

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)