docs: fix minor issues in middleware docs (#3436)

Author: fry69

docs/latest/concepts/middleware.md

@@ -39,7 +39,7 @@ excellent way to make http-related logic reusable on the server.
 Use the `define.middleware()` helper to get typings out of the box:
 
 ```ts middleware/my-middleware.ts
-import { define } from "./utils.ts";
+import { define } from "../utils.ts";
 
 const middleware = define.middleware(async (ctx) => {
   console.log("my middleware");
@@ -52,16 +52,16 @@ const middleware = define.middleware(async (ctx) => {
 Fresh ships with the following middlewares built-in:
 
 - [cors()](/docs/plugins/cors) - Set CORS HTTP headers
-- [csrf()](/docs/plugins/cors) - Set CSRF HTTP headers
+- [csrf()](/docs/plugins/csrf) - Set CSRF HTTP headers
 - [trailingSlash()](/docs/plugins/trailing-slashes) - Enforce trailing slashes
 
 ## Filesystem-based middlewares
 
 With file system based routing you can define a middleware in a `_middleware.ts`
 file inside the `routes/` folder or any of it's subfolders.
 
-```ts routes/foo/_middleware.ts
-import { define } from "./utils.ts";
+```ts routes/_middleware.ts
+import { define } from "../utils.ts";
 
 export default define.middleware(async (ctx) => {
   console.log("my middleware");
@@ -71,8 +71,8 @@ export default define.middleware(async (ctx) => {
 
 You can also export an array of middlewares:
 
-```ts routes/foo/_middleware.ts
-import { define } from "./utils.ts";
+```ts routes/_middleware.ts
+import { define } from "../utils.ts";
 
 const middleware1 = define.middleware(async (ctx) => {
   console.log("A");