Merge #18157: doc: fixing init.md documentation to not require rpcpassword

a2a03c3ca9 fixing documentation to not require rpcpassword (“jkcd”)

Pull request description:

  Configuration section in [doc/init.md](https://github.com/bitcoin/bitcoin/blob/master/doc/init.md) says user must set rpcpassword in order to run bitcoind. Since [71cbea](71cbeaad9a) fixed the code to use a cookie for authentication, it is not mandatory to set rpcpassword in the configuration.

  Fixes #16346

ACKs for top commit:
  hebasto:
    ACK a2a03c3ca9, modulo nit

Tree-SHA512: a62816fef78bed32200bb278cfc7aacf6ea154a60fdf5181927e48b806a1bd694bdf3ccec8362f5e58aad694d636c63f540323d54d85b61deaa417b95b8b56eb

doc/init.md

@@ -20,9 +20,9 @@ The macOS configuration assumes bitcoind will be set up for the current user.
 Configuration
 ---------------------------------
 
-At a bare minimum, bitcoind requires that the rpcpassword setting be set
+Running bitcoind as a daemon does not require any manual configuration. You may
-when running as a daemon.  If the configuration file does not exist or this
+set the `rpcauth` setting in the `bitcoin.conf` configuration file to override
-setting is not set, bitcoind will shut down promptly after startup.
+the default behaviour of using a special cookie for authentication.
 
 This password does not have to be remembered or typed as it is mostly used
 as a fixed token that bitcoind and client programs read from the configuration