bug#33921: 27.0.50; Default height is inconsistently - and apparently also incorrectly - documented

[Markus Triska]

In the Emacs man page, we find for the "-g" (--geometry) option:

    The width and height are specified in characters; the default is
    80 by 24.

In the Emacs info page ("C.8 Options for Window Size and Position"), we
find a different default height:

   The default frame width is 80 characters and the default height is
   40 lines.

However, when I start Emacs via "$ emacs -Q", I actually get a height
that is neither 24 nor 40, no matter how I count it: On a recent Debian
install with X toolkit, I get an initial window that comprises exactly
28 lines, and if I include the mode line and echo area, then the frame
height is 30, excluding the tool bar, menu bar and title bar.



In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2018-12-30 built on stretch
Repository revision: b0e6ecfc33077fb2dce904d315c8ef24e3649c9b
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.11604000
System Description: Debian GNU/Linux 9 (stretch)

Recent messages:
Loading /home/mt/prolog.el (source)...done
Loading /home/mt/public_html/ediprolog/ediprolog.el (source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Use +,-,0 for further adjustment [2 times]

Configured using:
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Configured features:
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TOOLKIT_SCROLL_BARS LUCID X11 XDBE XIM THREADS GMP

Important settings:
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Major mode: Fundamental

Minor modes in effect:
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