As requested for vim-snip (hrsh7th/vim-vsnip#225), I think it should be nice to be supported in LuaSnip as well...

Reference: https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/dev/lsp-extensions.md#snippet-textedit
Reference: hrsh7th/nvim-cmp#353 (comment)
Reference: simrat39/rust-tools.nvim#74