Update API documentation to always use , add compatibility shim to mcl_minecarts.is_rail() and mcl_minecarts.ge_rail_direction()

mods/ENTITIES/mcl_minecarts/API.md

@@ -77,7 +77,7 @@ Calculate the rail adjacency information for rail placement. Arguments are:
   - `ignore_neightbor_connections` - if true, don't check that a cart could leave
     the neighboring node from this direction.
 
-`mcl_minecarts:is_rail(position, railtype)`
+`mcl_minecarts.is_rail(position, railtype)`
 
 Determines if the node at `position` is a rail. If `railtype` is provided,
 determine if the node at `position` is that type of rail.
@@ -101,7 +101,7 @@ Converts the rail at `node_position`, if possible, another variant (curve, etc.)
 and rotates the node as needed so that rails connect together. `options` is
 passed thru to `mcl_minecarts.get_rail_connections()`
 
-`mcl_minecarts:get_rail_direction(rail_position, cart_direction)`
+`mcl_minecarts.get_rail_direction(rail_position, cart_direction)`
 
 Returns the next direction a cart traveling in the direction specified in `cart_direction`
 will travel from the rail located at `rail_position`.

mods/ENTITIES/mcl_minecarts/functions.lua

@@ -53,7 +53,13 @@ function mcl_minecarts:velocity_to_dir(v)
 	end
 end
 
-function mcl_minecarts:is_rail(pos, railtype)
+function mcl_minecarts.is_rail(self, pos, railtype)
+	-- Compatibility with mcl_minecarts:is_rail() usage
+	if self ~= mcl_minecarts then
+		railtype = pos
+		pos = self
+	end
+
 	local node_name = force_get_node(pos).name
 
 	if minetest.get_item_group(node_name, "rail") == 0 then
@@ -324,7 +330,13 @@ local function get_rail_direction_inner(pos, dir)
 
 	return dir
 end
-function mcl_minecarts:get_rail_direction(pos_, dir)
+function mcl_minecarts.get_rail_direction(self, pos_, dir)
+	-- Compatibility with mcl_minecarts:get_rail_direction() usage
+	if self ~= mcl_minecarts then
+		dir = pos_
+		pos_ = self
+	end
+
 	local pos = vector.round(pos_)
 
 	-- diagonal direction handling