fix(notify): bufhidden=wipe for notify buffers (#5517)

Closes #5514

Author: fannheyward

autoload/coc/float.vim

@@ -120,7 +120,7 @@ function! coc#float#create_float_win(winid, bufnr, config) abort
   let lines = get(a:config, 'lines', v:null)
   let bufnr = a:bufnr
   try
-    let bufnr = coc#float#create_buf(a:bufnr, lines, 'hide')
+    let bufnr = coc#float#create_buf(a:bufnr, lines, get(a:config, 'bufhidden', 'hide'))
   catch /E523:/
     " happens when using getchar() #3921
     return []

autoload/coc/notify.vim

@@ -207,6 +207,7 @@ function! coc#notify#create(lines, config) abort
       \ 'winblend': winblend,
       \ 'close': s:is_vim,
       \ 'border': border,
+      \ 'bufhidden': 'wipe',
       \ })
   let result = coc#float#create_float_win(0, 0, opts)
   if empty(result)