Vector3: Implement __concat operator overloading

Now you can do this:

local v = wea.Vector3.new(3, 4, 5)
print(v.."yay")

.tests/Vector3/concat.test.lua

@@ -0,0 +1,28 @@
+local Vector3 = require("worldeditadditions.utils.vector3")
+
+describe("Vector3.__concat", function()
+	it("should work when concatenating a Vector3 + Vector3", function()
+		local a = Vector3.new(3, 4, 5)
+		local b = Vector3.new(6, 7, 8)
+		
+		assert.are.is_true(
+			type(tostring(a .. b)) == "string"
+		)
+	end)
+	it("should work when concatenating a string + Vector3", function()
+		local a = "yay"
+		local b = Vector3.new(6, 7, 8)
+		
+		assert.are.is_true(
+			type(tostring(a .. b)) == "string"
+		)
+	end)
+	it("should work when concatenating a Vector3 + string", function()
+		local a = Vector3.new(3, 4, 5)
+		local b = "yay"
+		
+		assert.are.is_true(
+			type(tostring(a .. b)) == "string"
+		)
+	end)
+end)

worldeditadditions/utils/vector3.lua

@@ -389,5 +389,11 @@ function Vector3.__tostring(a)
 	return "("..a.x..", "..a.y..", "..a.z..")"
 end
 
+function Vector3.__concat(a, b)
+	if type(a) ~= "string" then a = tostring(a) end
+	if type(b) ~= "string" then b = tostring(b) end
+	return a .. b
+end
+
 
 return Vector3