Cleanup: use plural names for Main lists

Convention was not to but after discussion on 918941483f7e we agree its
best to change the convention.

Names now mostly follow RNA.

Some exceptions:

- Use 'nodetrees' instead of 'nodegroups'
  since the struct is called NodeTree.
- Use 'gpencils' instead of 'grease_pencil'
  since 'gpencil' is a common abbreviation in the C code.

Other exceptions:

- Leave 'wm' as it's a list of one.
- Leave 'ipo' as is for versioning.

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/makesrna/intern/rna_material.c b/source/blender/makesrna/intern/rna_material.c
index 1b21e554223..4c400b4fb2e 100644
--- a/source/blender/makesrna/intern/rna_material.c
+++ b/source/blender/makesrna/intern/rna_material.c
@@ -157,7 +157,7 @@ static void rna_Material_active_paint_texture_index_update(Main *bmain, Scene *U
 
 	if (ma->texpaintslot) {
 		Image *image = ma->texpaintslot[ma->paint_active_slot].ima;
-		for (sc = bmain->screen.first; sc; sc = sc->id.next) {
+		for (sc = bmain->screens.first; sc; sc = sc->id.next) {
 			wmWindow *win = ED_screen_window_find(sc, bmain->wm.first);
 			if (win == NULL) {
 				continue;