fix broken links (#441)

Co-authored-by: Igor Aleksanov <popzxc@yandex.ru>
Co-authored-by: Altug Sahin <altugsahin@gmail.com>
Co-authored-by: Rob Ede <robjtede@icloud.com>

forms/multipart-async-std/README.md

@@ -2,6 +2,11 @@
 
 ### Run
 
+```bash
+cd forms/multipart-async-std
+cargo run
+```
+
 ``` open web browser to localhost:3000 and upload file(s) ```
 
 ### Result

forms/multipart-s3/README.md

@@ -4,7 +4,7 @@ Receive multiple data in multipart form in JSON format and receive it as a struc
 
 # usage
 ```
-cd examples/multipart+s3
+cd forms/multipart-s3
 ```
 1. copy .env.example .env
 2. edit .env  AWS_ACCESS_KEY_ID=you_key
@@ -14,7 +14,7 @@ cd examples/multipart+s3
 
 # Running Server
 ```
-cd examples/multipart+s3
+cd forms/multipart-s3
 cargo run (or ``cargo watch -x run``)
 ```
 http://localhost:3000   

forms/multipart/README.md

@@ -2,6 +2,11 @@
 
 ### Run
 
+```bash
+cd forms/multipart
+cargo run
+```
+
 ``` open web browser to localhost:3000 and upload file(s) ```
 
 ### Result