Use modern autocmd_add() and autocmd_delete() APIs

adapters/vim/collab.vim

@@ -147,11 +147,20 @@ export def Connect(room_name: string): void
     Send({type: 'connect', room: room_name})
 
     # set up autocmds to send changes
-    augroup CollabVim
-        autocmd!
-        autocmd TextChanged,TextChangedI * call SendBuffer()
-        autocmd CursorMoved,CursorMovedI <buffer> call SendCursor()
-    augroup END
+    autocmd_add([
+        {
+            group: 'CollabVim',
+            event: ['TextChanged', 'TextChangedI'],
+            pattern: '*',
+            cmd: 'SendBuffer()'
+        },
+        {
+            group: 'CollabVim',
+            event: ['CursorMoved', 'CursorMovedI'],
+            bufnr: bufnr(),
+            cmd: 'SendCursor()'
+        }
+    ])
 enddef
 
 export def Disconnect(): void
@@ -165,9 +174,7 @@ export def Disconnect(): void
     connected = false
     ready = false
     room = ""
-    augroup CollabVim
-        autocmd!
-    augroup END
+    autocmd_delete([{group: 'CollabVim'}])
     echom '[collab] disconnected'
 enddef