Margins pop-up only accepts integer values

Summary:

When specifying margins using the interactive pop-out dialog, only integer values can be specified; units cannot be specified

Steps to reproduce:

• open Inkscape

• Switch to "Page view"

• (Optionally: Confirm that a non-integer margin can be specified, e.g. 30.5 mm)

• Click the

  

  icon to launch the margin editor dialog

• Only integers can be entered into the "Margins" box

What happened?

"Margins" values were rounded to integers. Selecting a box edits rounds that margin (but not others, which retain their original non-integer value)

What should have happened?

A user should be able to specify non-integer values, AND units, in the dialog box.

Version info

Inkscape 1.3 (0e150ed6c4, 2023-07-21)

    GLib version:     2.76.4
    GTK version:      3.24.38
    glibmm version:   2.66.6
    gtkmm version:    3.24.7
    libxml2 version:  2.11.4
    libxslt version:  1.1.38
    Cairo version:    1.17.7
    Pango version:    1.50.14
    HarfBuzz version: 8.0.1

    OS version:       Windows 10 22H2