Add new checkbox icons

novelwriter/assets/icons/typicons_dark/icons.conf

@@ -21,7 +21,7 @@ backward        = typ_chevron-left.svg
 bookmark        = typ_bookmark.svg
 bullet-off      = typ_media-record-outline.svg
 bullet-on       = typ_media-record.svg
-check           = typ_tick.svg
+checked         = mixed_input-checked.svg
 close           = typ_times.svg
 cls_archive     = typ_delete.svg
 cls_character   = typ_user.svg
@@ -41,13 +41,14 @@ forward         = typ_chevron-right.svg
 maximise        = typ_arrow-maximise.svg
 menu            = typ_th-menu.svg
 minimise        = typ_arrow-minimise.svg
+noncheckable    = mixed_input-none.svg
 proj_chapter    = mixed_document-chapter.svg
 proj_details    = typ_th-list-grey.svg
 proj_document   = typ_document-text.svg
 proj_folder     = typ_folder.svg
 proj_note       = mixed_document-note.svg
-proj_section    = mixed_document-section.svg
 proj_scene      = mixed_document-scene.svg
+proj_section    = mixed_document-section.svg
 proj_stats      = typ_chart-bar-grey.svg
 proj_title      = mixed_document-title.svg
 reference       = typ_at.svg
@@ -70,6 +71,7 @@ status_stats    = typ_chart-bar-grey.svg
 status_time     = typ_stopwatch-grey.svg
 sticky-off      = typ_pin-outline.svg
 sticky-on       = typ_pin.svg
+unchecked       = mixed_input-unchecked.svg
 up              = typ_chevron-up.svg
 view_build      = typ_export.svg
 view_editor     = mixed_edit.svg