Add magic curl syntax

Co-authored-by: Georgi Gerganov <[email protected]>

Author: felrock

examples/server/README.md

@@ -46,7 +46,7 @@ options:
 ```
 curl 127.0.0.1:8080/inference \
 -H "Content-Type: multipart/form-data" \
--F file="<file-path>" \
+-F file="@<file-path>" \
 -F temperature="0.2" \
 -F response-format="json"
 ```