Spelling fixes in comments and descriptions, patch by luzpaz.

Differential Revision: https://developer.blender.org/D3668

source/blender/nodes/shader/node_shader_util.c

@@ -143,7 +143,7 @@ void node_gpu_stack_from_data(struct GPUNodeStack *gs, int type, bNodeStack *ns)
 	memset(gs, 0, sizeof(*gs));
 
 	if (ns == NULL) {
-		/* node_get_stack() will generate NULL bNodeStack pointers for unknown/unsuported types of sockets... */
+		/* node_get_stack() will generate NULL bNodeStack pointers for unknown/unsupported types of sockets... */
 		zero_v4(gs->vec);
 		gs->link = NULL;
 		gs->type = GPU_NONE;