It turns out these few icons were missed when the color and size
information was removed from the SVG icons that replaced XPM icons for
Customize buffer.
* etc/images/down.svg:
* etc/images/left.svg:
* etc/images/right.svg:
* etc/images/up.svg: Don't define foreground; this means they will use
the foreground of the currently defined face instead. (Bug#51556)
(cherry picked from commit 11702a6dd7)
* etc/images/checkbox-mixed.svg:
* etc/images/checked.svg:
* etc/images/down.svg:
* etc/images/left.svg:
* etc/images/radio-checked.svg:
* etc/images/radio-mixed.svg:
* etc/images/radio.svg:
* etc/images/right.svg:
* etc/images/unchecked.svg:
* etc/images/up.svg: New files from the Adwaita Icon Theme (made by
the GNOME project). The background color was changed from gray to
none to use the same colors as the current face instead. (Bug#47074)
* etc/images/README: Add license information for the above new files.
* lisp/wid-edit.el (widget-image-conversion): Prefer SVG if it exists.
(radio-button): Rename radio buttons to "radio-checked" and
"radio". These files did not exist before.
