bug#28648: Make mode-line number display consistent when both line and col numbers are shown.

[Drew Adams <drew.adams@oracle.com>]

Apologies (again) for not reading the thread.

FYI, my library `modeline-posn.el' modifies the default value of
`mode-line-position' to allow for some features and customizing.

(I'm guessing that whatever changes you're making to the vanilla
value will complicate things for me a bit, but that's life.)

You _might_ want to take a look at `modeline-posn.el', to see
if it or parts of it might help.

It has, for example, option `modelinepos-style', which lets
you show info about the size of the active region in the
mode-line-position part of the mode-line.  You can choose
any of these:

 * "_ ch, _ l" (or "_ rows, _ cols", if a rectangle is selected)

 * "_ chars"

 * "_ bytes"

 * the result of a custom format string and any args it expects

(There are some other features too, such as using a different
face on the region info when the current command is acting on
the active region.  For example, a command such as `query-replace'
acts differently when the region is active - when it is, the
face changes to avert you to this fact.)

The code is here, if you're interested:
https://www.emacswiki.org/emacs/download/modeline-posn.el

A description is here:
https://www.emacswiki.org/emacs/ModeLinePosition