nixpkgs/neovim: show filename in telescope preview

.config/nixpkgs/neovim/plugins.lua

@@ -12,6 +12,8 @@ require('telescope').setup({
       prompt_position = 'top',
     },
     sorting_strategy = 'ascending',
+    -- use filename as preview window title
+    dynamic_preview_title = true,
   },
   pickers = {
     buffers = {