Merge bitcoin/bitcoin#28283: doc: clarify cookie generation in JSON-RPC-interface.md

bdb2e8d Update JSON-RPC-interface.md (iamcarlos94)

Pull request description:

  clarifying when the .cookie file is generated

ACKs for top commit:
  maflcko:
     lgtm ACK bdb2e8d
  achow101:
    ACK bdb2e8d

Tree-SHA512: 5a19b9892917126980bd3260f6035a8b2c5c9a9cfd16261d5364713ffa4816f1604e8bd3298fcf7ca7be072f33cd5a9f4e0a89cfee77ae90dc0b201e4abc0f3f

Author: achow101

doc/JSON-RPC-interface.md

@@ -128,7 +128,7 @@ RPC interface will be abused.
     Instead, expose it only on the host system's localhost, for example:
     `-p 127.0.0.1:8332:8332`
 
-- **Secure authentication:** By default, Bitcoin Core generates unique
+- **Secure authentication:** By default, when no `rpcpassword` is specified, Bitcoin Core generates unique
   login credentials each time it restarts and puts them into a file
   readable only by the user that started Bitcoin Core, allowing any of
   that user's RPC clients with read access to the file to login