The function signature for the send RPC is:
0send [{"address":amount,...},{"data":"hex"},...] ( conf_target "estimate_mode" fee_rate options version )
The last example in the manpage is missing the fee_rate arg, but is trying to specify the options arg, by index. The parser confuses the intended options arg as the missing fee_rate arg.
See:
0$ bitcoin-cli -rpcuser=doggman -rpcpassword=donkey -rpcport=18554 -regtest send '{"bcrt1qusm48zmlzwr32csxdw4ar7atw260h22c9ten9l": 0.1}' 1 economical '{"add_to_wallet": false, "inputs": [{"txid":"0b7e1a471dc948b7a6187936b16e6d7d9833629b2f9dd8a392eb89928f63aaad", "vout":0}]}'
1error code: -8
2error message:
3Cannot specify both conf_target and fee_rate. Please provide either a confirmation target in blocks for automatic fee estimation, or an explicit fee rate.
vs
0$ bitcoin-cli -rpcuser=doggman -rpcpassword=donkey -rpcport=18554 -regtest send '{"bcrt1qusm48zmlzwr32csxdw4ar7atw260h22c9ten9l": 0.1}' 1 economical null '{"add_to_wallet": false, "inputs": [{"txid":"0b7e1a471dc948b7a6187936b16e6d7d9833629b2f9dd8a392eb89928f63aaad", "vout":0}]}'
1{
2 "psbt": "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",
3 "txid": "625b71b314a6ac4f738634e29dc007cd5edc0427c1ae96ab706d06a62910cea2",
4 "hex": "02000000000101adaa638f9289eb92a3d89d2f9b6233987d6d6eb1367918a6b748c91d471a7e0b0000000000fdffffff0244760f0400000000160014a4b0f026efb01511cb40080a01bd29b24ed455dd8096980000000000160014e437538b7f13871562066babd1fbab72b4fba9580247304402204953578a5b52bb0f47da8759c8a8a3056fdd05561e2cf1c1ebdf0f4bbf23c6320220426373b317cd4f48b334d21e2e79091e858bb10c566eec9939d627a3a612a79f012103454a758552c81a56a310704c33aea41e7c162de6101b3ebbe38ea84615776b1900000000",
5 "complete": true
6}