This was a requested follow-up to #19133 and #17700 to alleviate confusion and head-scratching by people following tutorials that use generate. See #19455 (comment) below, #19133 (comment) and #17700 (comment).
before
$ bitcoin-cli help generate
help: unknown command: generate
$ bitcoin-cli generate
error code: -32601
error message:
Method not found
after
$ bitcoin-cli help generate
generate ( nblocks maxtries ) has been replaced by the -generate cli option. Refer to -help for more information.
$ bitcoin-cli generate
error code: -32601
error message:
generate ( nblocks maxtries ) has been replaced by the -generate cli option. Refer to -help for more information.
In the general help it remains hidden, as requested by laanwj.
$ bitcoin-cli help
== Generating ==
generateblock "output" ["rawtx/txid",...]
generatetoaddress nblocks "address" ( maxtries )
generatetodescriptor num_blocks "descriptor" ( maxtries )