Update mg_printf.md

docs/c-api/net.h/mg_printf.md

@@ -6,7 +6,7 @@ signature: |
   int mg_printf(struct mg_connection *, const char *fmt, ...);
 ---
 
-Send `printf`-style formatted data to the connection.
+Sends `printf`-style formatted data to the connection.
 
 See `mg_send` for more details on send semantics.