doc: fix `added:` info for `outgoingMessage.writable*`

- `outgoingMessage.writableCorked` was added to Node.js v13.2.0 via
  62e15a793a and backported to Node.js v12.16.0 via db8144be31.
- `outgoingMessage.writableEnded` was added to Node.js v12.9.0 via
  f9b61d2bc7.
- `outgoingMessage.writableFinished` was added to Node.js v12.7.0 via
  06d0abea0d.
- `outgoingMessage.writableHighWaterMark`,
  `outgoingMessage.writableLength`, and
  `outgoingMessage.writableObjectMode` were added to Node.js v12.9.0 via
  16e001112c.

PR-URL: https://github.com/nodejs/node/pull/42737
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
Reviewed-By: Mestery <mestery@protonmail.com>
Reviewed-By: Ricky Zhou <0x19951125@gmail.com>

doc/api/http.md

@@ -2745,7 +2745,9 @@ See [`writable.uncork()`][]
 ### `outgoingMessage.writableCorked`
 
 <!-- YAML
-added: v14.0.0
+added:
+  - v13.2.0
+  - v12.16.0
 -->
 
 * {number}
@@ -2756,7 +2758,7 @@ This `outgoingMessage.writableCorked` will return the time how many
 ### `outgoingMessage.writableEnded`
 
 <!-- YAML
-added: v13.0.0
+added: v12.9.0
 -->
 
 * {boolean}
@@ -2768,7 +2770,7 @@ purpose, use `message.writableFinished` instead.
 ### `outgoingMessage.writableFinished`
 
 <!-- YAML
-added: v13.0.0
+added: v12.7.0
 -->
 
 * {boolean}
@@ -2778,7 +2780,7 @@ Readonly. `true` if all data has been flushed to the underlying system.
 ### `outgoingMessage.writableHighWaterMark`
 
 <!-- YAML
-added: v13.0.0
+added: v12.9.0
 -->
 
 * {number}
@@ -2793,7 +2795,7 @@ buffered by the socket.
 ### `outgoingMessage.writableLength`
 
 <!-- YAML
-added: v13.0.0
+added: v12.9.0
 -->
 
 * {number}
@@ -2804,7 +2806,7 @@ bytes (or objects) in the buffer ready to send.
 ### `outgoingMessage.writableObjectMode`
 
 <!-- YAML
-added: v13.0.0
+added: v12.9.0
 -->
 
 * {boolean}