Stylua formatting (#785)

Uses Stylua to format all existing Lua files, and adds a CI check in
`lint` to pin this improvement. Excludes formatting dependencies, of
course.

plugin/src/Reconciler/hydrate.spec.lua

@@ -91,7 +91,7 @@ return function()
 				ClassName = "Folder",
 				Name = "Root",
 				Properties = {},
-				Children = {"CHILD1", "CHILD2"},
+				Children = { "CHILD1", "CHILD2" },
 			},
 
 			CHILD1 = {
@@ -126,4 +126,4 @@ return function()
 		expect(knownInstances.fromIds["CHILD1"]).to.equal(child1)
 		expect(knownInstances.fromIds["CHILD2"]).to.equal(child2)
 	end)
-end
+end