Add piston and pressure plate help

mods/ITEMS/REDSTONE/mesecons_pistons/init.lua

@@ -151,9 +151,13 @@ local pistonspec_normal = {
 	piston_up   = "mesecons_pistons:piston_up_normal_off",
 }
 
+local usagehelp_piston = "This block can have one of 6 possible orientations. On placement, the pusher will face towards your reverse looking direction."
+
 -- offstate
 minetest.register_node("mesecons_pistons:piston_normal_off", {
 	description = "Piston",
+	_doc_items_longdesc = "A piston is a redstone component with a pusher which pushes the block or blocks in front of it when it is supplied with redstone power. Not all blocks can be pushed, however.",
+	_doc_items_usagehelp = usagehelp_piston,
 	tiles = {
 		"mesecons_piston_top.png", 
 		"mesecons_piston_bottom.png", 
@@ -244,6 +248,9 @@ local pistonspec_sticky = {
 -- offstate
 minetest.register_node("mesecons_pistons:piston_sticky_off", {
 	description = "Sticky Piston",
+	_doc_items_longdesc = "A sticky piston is a redstone component with a sticky pusher which can be extended and retracted. It extends when it is supplied with redstone power. When the pusher extends, it pushes the block or blocks in front of it. When it retracts, it pulls back the single block in front of it. Note that not all blocks can be pushed or pulled.",
+	_doc_items_usagehelp = usagehelp_piston,
+
 	tiles = {
 		"mesecons_piston_top.png", 
 		"mesecons_piston_bottom.png", 

mods/ITEMS/REDSTONE/mesecons_pressureplates/init.lua

@@ -71,6 +71,7 @@ function mesecon:register_pressure_plate(offstate, onstate, description, texture
 		groups = groups_off,
 		is_ground_content = false,
 	    	description = description,
+		_doc_items_longdesc = "A pressure place is a redstone component which supplies its surrounding blocks with redstone power while someone or something rests on top of it.",
 		pressureplate = ppspec,
 		on_timer = pp_on_timer,
 		sounds = sounds,