[gnome-builder] plugins/line-spacing: remove line-spacing plugin

[Christian Hergert <chergert src gnome org>]

commit 614feded153640d56df1ebe224117105495c87b0
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jul 11 22:57:52 2022 -0700

    plugins/line-spacing: remove line-spacing plugin
    
    This is handled differently now in IdeSourceView using CSS like Text
    Editor does.

 .../line-spacing/gbp-line-spacing-buffer-addin.c   | 157 ---------------------
 .../line-spacing/gbp-line-spacing-buffer-addin.h   |  31 ----
 src/plugins/line-spacing/line-spacing-plugin.c     |  36 -----
 .../line-spacing/line-spacing.gresource.xml        |   6 -
 src/plugins/line-spacing/line-spacing.plugin       |  10 --
 src/plugins/line-spacing/meson.build               |  12 --
 6 files changed, 252 deletions(-)