Fix glass panes sides (#2500)

game_api.txt

@@ -773,7 +773,11 @@ Creates panes that automatically connect to each other
 ### Pane definition
 
 	{
-		textures = {"texture for sides", (unused), "texture for top and bottom"}, -- More tiles aren't supported
+		textures = {
+			"texture for front and back",
+			(unused),
+			"texture for the 4 edges"
+		}, -- More tiles aren't supported
 		groups = {group = rating}, -- Uses the known node groups, see [Known damage and digging time defining groups]
 		sounds = SoundSpec,        -- See [#Default sounds]
 		recipe = {{"","","","","","","","",""}}, -- Recipe field only

mods/xpanes/init.lua

@@ -105,7 +105,14 @@ function xpanes.register_pane(name, def)
 		inventory_image = def.inventory_image,
 		wield_image = def.wield_image,
 		paramtype2 = "facedir",
-		tiles = {def.textures[3], def.textures[3], def.textures[1]},
+		tiles = {
+				def.textures[3],
+				def.textures[3],
+				def.textures[3],
+				def.textures[3],
+				def.textures[1],
+				def.textures[1]
+		},
 		groups = flatgroups,
 		drop = "xpanes:" .. name .. "_flat",
 		sounds = def.sounds,