Inconsistent behaviour of snippets with escaped dollar sign \\$

[Mattias-]

Make sure you have done the following

• I have updated to the latest version of blink.cmp
• I have read the README

Bug Description

Hello I'm debugging inconsistent behaviour of snippets with escaped dollar sign \\$.
I found it while migrating from using LuaSnip for my VSCode style snippets to the native snippets handling in blink.

Run nvim with repro files:

nvim -u repro.lua

Enter insert mode and complete the snippets:

ie1<C-y><cr>e2<C-y><esc>

Output:

echo "e1 all: \$@ arg0: \$0"
echo "e2 all: $@ arg0: $0 extra: EXTRA"

Expected output:

echo "e1 all: $@ arg0: $0"
echo "e2 all: $@ arg0: $0 extra: EXTRA"

Relevant configuration

repro.lua:

vim.env.LAZY_STDPATH = ".repro"
load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()

require("lazy.minit").repro({
    spec = {
        {
            'saghen/blink.cmp',
            version = 'v0.8.2',
            dependencies = 'rafamadriz/friendly-snippets',
            opts = {
                sources = {
                    default = { 'snippets' },
                    providers = {
                        snippets = {
                            opts = {
                                search_paths = { './' } -- With this we can find the all.json file with snippets in the same directory
                            }
                        }
                    }
                },
            },
            opts_extend = { "sources.default" },
        }
    },
})

all.json:

{
  "e1": {
    "prefix": "e1",
    "body": "echo \"e1 all: \\$@ arg0: \\$0\""
  },
  "e2": {
    "prefix": "e2",
    "body": "echo \"e2 all: \\$@ arg0: \\$0 extra: ${1:EXTRA}\""
  }
}

neovim version

v0.10.2

blink.cmp version: branch, tag, or commit

v0.8.2