implement `didRenameFiles`

I came up with this, it would be great if that was handled by default :)

https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspace_didRenameFiles

EDIT: fix wrong implementation and add WillRenameNode

local function make_rename_params(old_fname, new_fname)
    return {
        files = {
            {
                oldUri = vim.uri_from_fname(old_fname),
                newUri = vim.uri_from_fname(new_fname),
            },
        },
    }
end

local Event = api.events.Event
api.events.subscribe(Event.NodeRenamed, function(data)
    local clients = vim.lsp.get_active_clients()
    local params = make_rename_params(data.old_name, data.new_name)
    for _, client in ipairs(clients) do
        local didRename = vim.tbl_get(client, "server_capabilities", "workspace", "fileOperations", "didRename")
        if didRename ~= nil then
            client.notify("workspace/didRenameFiles", params)
        end
    end
end)

api.events.subscribe(Event.WillRenameNode, function(data)
    local clients = vim.lsp.get_active_clients()
    local params = make_rename_params(data.old_name, data.new_name)
    for _, client in ipairs(clients) do
        local willRename = vim.tbl_get(client, "server_capabilities", "workspace", "fileOperations", "willRename")
        if willRename ~= nil then
            local resp = client.request_sync("workspace/willRenameFiles", params, 1000)
            if resp and resp.result ~= nil then
                vim.lsp.util.apply_workspace_edit(resp.result, client.offset_encoding)
            end
        end
    end
end)

Start with the linked LSP 3.17 workspace/didRenameFiles specification and the nvim-tree event APIs shown for NodeRenamed and WillRenameNode. Trace how active LSP clients and file-operation capabilities are exposed, then verify that rename notifications and pre-rename requests behave correctly, including workspace edits; done means the supported LSP rename operations work by default without breaking file renames.