rust-analyzer.completion.snippets.custom was not covered as expected, but was added instead

What's the output of :CocInfo

## versions

vim version: VIM - Vi IMproved 9.1 9010000
node version: v21.2.0
coc.nvim version: 0.0.82-e108777 2023-11-27 04:48:08 +0100
coc.nvim directory: /home/lrne/.vim/plugged/coc.nvim
term: dumb
platform: linux

## Log of coc.nvim

2024-01-30T12:44:46.710 INFO (pid:19049) [plugin] - coc.nvim initialized with node: v21.2.0 after 365
2024-01-30T12:44:49.110 INFO (pid:19049) [attach] - receive notification: showInfo []

What's the output of :CocCommand rust-analyzer.serverVersion

rust-analyzer 1.77.0-nightly (bf8716f1 2023-12-24)

What's your coc-rust-analyzer version? You can get it from :CocList extensions

* coc-rust-analyzer 0.75.1

coc-settings.json

"rust-analyzer.completion.snippets.custom": {
    "Abc::new": {
        "postfix": "abc",
        "body": "Abc::new(${receiver})",
        "scope": "expr"
    }
}

X.a
           arc~ (use std::sync::Arc) Put the expression into an `Arc`              S [LS]
           abc~ Abc::new                                                           S [LS]

expected

Old snippets should be overwritten and cleared instead of adding new ones to the old ones. like let letm .let .rc

fannheyward / coc-rust-analyzer

rust-analyzer.completion.snippets.custom was not covered as expected, but was added instead #1222

coc-settings.json

expected