Text highligthing should depend on desktop theme

[bitboy85]

 * Xed version 3.2.2
 * Distribution - Linuxmint Cinnamon

Issue
Colors for text highlighting should depend on selected desktop theme.
For example: Having a dark theme, the default xml-style makes parts, in this case comments, barely readable.

Steps to reproduce
Select a dark window theme
Open a xml document

[darkshram]

It's not up to Xed, but gtksourceview4 (a GNOME controlled project). Any text editor (gedit/gnome-text-editor, pluma, xed, mousepad, etc.) using gtksourceview4 will have this same issue when switching to a dark theme.

Xed uses gtksourceview4, which has support for styles. Styles may be copied into /usr/share/gtksourceview-4/styles or ~/.local/share/gtksourceview-4/styles/. Unfortunately gtksourceview is designed to be used only with Adwaita and its [GNOME] developers do not care about any other desktop theme. But there are several styles that fit quite good with dark themes. The default gtksourceview style (tango) has no color defined for background and that's why it looks really bad with dark themes.

You may get styles for gtksourceview at: https://wiki.gnome.org/Projects/GtkSourceView/StyleSchemes

My recommendation is to use darkmate, which fits pretty well with light and dark themes:

And do not forget to enable the "Dark theme" feature.

And the result will be:

Screenshot was taken using Dracula theme.