ext/curl: Update stub CURLOPT_ENCODING @cvalue to CURLOPT_ACCEPT_ENCODING

In Curl 7.21.6, the `CURLOPT_ENCODING` constant was renamed to `CURLOPT_ACCEPT_ENCODING`.

`CURLOPT_ENCODING` is deprecated from Curl 7.21.6. It still provides
`CURLOPT_ENCODING` from `CURLOPT_ACCEPT_ENCODING` for backward compatibility.

However, now that PHP requires Curl 7.61, we can safely use the new `CURLOPT_ACCEPT_ENCODING`
constant.

Author: Ayesh

NEWS

@@ -7,6 +7,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-15644 (Asymmetric visibility doesn't work with hooks). (ilutov)
   . Implemented lazy objects RFC. (Arnaud)
 
+- Curl:
+  . Added CURLOPT_SERVER_RESPONSE_TIMEOUT, which was formerly known as
+    CURLOPT_FTP_RESPONSE_TIMEOUT. (Ayesh Karunaratne)
+
 - DOM:
   . Fixed bug GH-13988 (Storing DOMElement consume 4 times more memory in
     PHP 8.1 than in PHP 8.0). (nielsdos)
@@ -32,10 +36,6 @@ PHP                                                                        NEWS
     EAI_SYSTEM not found). (nielsdos)
   . Implemented asymmetric visibility for properties. (ilutov)
 
-- Curl:
-  . Added CURLOPT_SERVER_RESPONSE_TIMEOUT, which was formerly known as
-    CURLOPT_FTP_RESPONSE_TIMEOUT. (Ayesh Karunaratne)
-
 - Date:
   . Fixed bug GH-13773 (DatePeriod not taking into account microseconds for end
     date). (Mark Bennewitz, Derick)

ext/curl/curl.stub.php

@@ -84,7 +84,8 @@
 const CURLOPT_EGDSOCKET = UNKNOWN;
 /**
  * @var int
- * @cvalue CURLOPT_ENCODING
+ * @cvalue CURLOPT_ACCEPT_ENCODING
+ * @alias CURLOPT_ACCEPT_ENCODING
  */
 const CURLOPT_ENCODING = UNKNOWN;
 /**