Add wildcards example

examples/luau/queries/wildcards.luau

@@ -0,0 +1,37 @@
+local jecs = require("@jecs")
+local pair = jecs.pair
+local world = jecs.World.new()
+local Name = world:component()
+
+local function named(ctr, name)
+    local e = ctr(world)
+    world:set(e, Name, name)
+    return e
+end
+local function name(e)
+    return world:get(e, Name)
+end
+
+local Eats = world:component()
+local Apples = named(world.entity, "Apples")
+local Oranges = named(world.entity, "Oranges")
+
+local bob = named(world.entity, "Bob")
+world:set(bob, pair(Eats, Apples), 10)
+
+local alice = named(world.entity, "Alice")
+world:set(alice, pair(Eats, Oranges), 5)
+
+-- Aliasing the wildcard to symbols improves readability and ease of writing
+local __ = jecs.Wildcard
+
+-- Create a query that matches edible components
+for entity, amount in world:query(pair(Eats, __)) do
+    -- Iterate the query
+    local food = world:target(entity, Eats)
+    print(`{name(entity)} eats {amount} {name(food)}`)
+end
+
+-- Output:
+--  Alice eats 5 Oranges
+--  Bob eats 10 Apples