lsp(rust): work around server cancelled request issue with latest rust

Ref.: neovim/neovim#30985 (comment)

lua/nxvim/lsp/plugins/mason/lspconfig.lua

@@ -42,6 +42,14 @@ mason_lspconfig.setup_handlers({
 			server_opts.root_dir = lspconfig.util.root_pattern("deno.json", "deno.jsonc")
 		elseif server == "jsonls" then
 			server_opts.init_options = { provideFormatter = false } -- Use prettierd as formatter.
+		elseif server == "rust_analyzer" then
+			for _, method in ipairs({ "textDocument/diagnostic", "workspace/diagnostic" }) do
+				local default_diagnostic_handler = vim.lsp.handlers[method]
+				vim.lsp.handlers[method] = function(err, result, context, config)
+					if err ~= nil and err.code == -32802 then return end
+					return default_diagnostic_handler(err, result, context, config)
+				end
+			end
 		elseif server == "zls" then
 			vim.g.zig_fmt_autosave = 0
 		end