Wireframe: Add slider to hide edges from coplanar faces

The default behaviour is to show the same amount of edges as 2.7.
The slider makes it possible to show all edges or even less.

release/scripts/startup/bl_ui/space_view3d.py

@@ -3573,7 +3573,13 @@ class VIEW3D_PT_overlay(Panel):
         col.prop(overlay, "show_relationship_lines")
         col.prop(overlay, "show_motion_paths")
         col.prop(overlay, "show_face_orientation")
-        col.prop(overlay, "show_wireframes")
+
+        row = col.row()
+        row.prop(overlay, "show_wireframes")
+        sub = row.row()
+        sub.active = overlay.show_wireframes
+        sub.prop(overlay, "wireframe_threshold", text="")
+
         col.prop(overlay, "show_backface_culling")
 
         if shading.type == "MATERIAL":