KNOWN_BUGS: renames instead of locking for atomic operations

Closes #6882
Closes #6884

docs/KNOWN_BUGS

@@ -112,6 +112,7 @@ problems may have been fixed or changed somewhat since this was written!
  11.13 wakeup socket disconnect causes havoc
  11.14 Multi perform hangs waiting for threaded resolver
  11.15 CURLOPT_OPENSOCKETPAIRFUNCTION is missing
+ 11.16 libcurl uses renames instead of locking for atomic operations
 
  12. LDAP
  12.1 OpenLDAP hangs after returning results
@@ -868,6 +869,15 @@ problems may have been fixed or changed somewhat since this was written!
 
  https://github.com/curl/curl/issues/5747
 
+11.16 libcurl uses renames instead of locking for atomic operations
+
+ For saving cookies, alt-svc and hsts files. This is bad when for example the
+ file is stored in a directory where the application has no write permission
+ but it has permission for the file.
+
+ https://github.com/curl/curl/issues/6882
+ https://github.com/curl/curl/pull/6884
+
 12. LDAP
 
 12.1 OpenLDAP hangs after returning results