man: remove docs for deprecated --api-cors-header

It was deprecated in 27.0x through 7ea9acc97f4c884ecdaebd06ed0353b28263d118,
and removed in ae96ce866f4b3dc09dc4eab019d7725a63623d94.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

man/dockerd.8.md

@@ -7,7 +7,6 @@ dockerd - Enable daemon mode
 **dockerd**
 [**--add-runtime**[=*[]*]]
 [**--allow-nondistributable-artifacts**[=*[]*]]
-[**--api-cors-header**=[=*API-CORS-HEADER*]]
 [**--authorization-plugin**[=*[]*]]
 [**-b**|**--bridge**[=*BRIDGE*]]
 [**--bip**[=*BIP*]]
@@ -136,10 +135,6 @@ $ sudo dockerd --add-runtime runc=runc --add-runtime custom=/usr/local/bin/my-ru
   artifacts to private registries and ensure that you are in compliance with
   any terms that cover redistributing nondistributable artifacts.
 
-**--api-cors-header**=""
-  Set CORS headers in the Engine API. Default is cors disabled. Give urls like
-  "http://foo, http://bar, ...". Give "\*" to allow all.
-
 **--authorization-plugin**=""
   Set authorization plugins to load