doc: writableFinished is true before 'finish'

PR-URL: nodejs#28811
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: ronag

doc/api/http.md

@@ -1480,7 +1480,9 @@ added: v12.7.0
 
 * {boolean}
 
-Is `true` if all data has been flushed to the underlying system.
+Is `true` if all data has been flushed to the underlying system, immediately
+before the [`'finish'`][] event is emitted.
+
 
 ### response.writeContinue()
 <!-- YAML
@@ -2198,6 +2200,7 @@ not abort the request or do anything besides add a `'timeout'` event.
 [`agent.createConnection()`]: #http_agent_createconnection_options_callback
 [`agent.getName()`]: #http_agent_getname_options
 [`destroy()`]: #http_agent_destroy
+[`'finish'`]: #http_event_finish
 [`getHeader(name)`]: #http_request_getheader_name
 [`http.Agent`]: #http_class_http_agent
 [`http.ClientRequest`]: #http_class_http_clientrequest

doc/api/stream.md

@@ -496,7 +496,7 @@ added: v12.6.0
 
 * {boolean}
 
-Is `true` if after the [`'finish'`][] event has been emitted.
+Is set to `true` immediately before the [`'finish'`][] event is emitted.
 
 ##### writable.writableHighWaterMark
 <!-- YAML