fix: allow previewer win customization (#460)

lua/telescope/pickers.lua

@@ -364,7 +364,7 @@ function Picker:find()
     preview_win, preview_opts = popup.create('', popup_opts.preview)
     preview_bufnr = a.nvim_win_get_buf(preview_win)
 
-    a.nvim_win_set_option(preview_win, 'winhl', 'Normal:TelescopeNormal')
+    a.nvim_win_set_option(preview_win, 'winhl', 'Normal:TelescopePreviewNormal')
     a.nvim_win_set_option(preview_win, 'winblend', self.window.winblend)
     local preview_border_win = preview_opts and preview_opts.border and preview_opts.border.win_id
     if preview_border_win then

lua/telescope/previewers/buffer_previewer.lua

@@ -125,7 +125,7 @@ previewers.new_buffer_previewer = function(opts)
       vim.api.nvim_win_set_buf(status.preview_win, bufnr)
 
       -- TODO(conni2461): We only have to set options once. Right?
-      vim.api.nvim_win_set_option(status.preview_win, 'winhl', 'Normal:Normal')
+      vim.api.nvim_win_set_option(status.preview_win, 'winhl', 'Normal:TelescopePreviewNormal')
       vim.api.nvim_win_set_option(status.preview_win, 'signcolumn', 'no')
       vim.api.nvim_win_set_option(status.preview_win, 'foldlevel', 100)
       vim.api.nvim_win_set_option(status.preview_win, 'wrap', false)

plugin/telescope.vim

@@ -6,6 +6,9 @@ highlight default link TelescopeMultiSelection Type
 " "Normal" in the floating windows created by telescope.
 highlight default link TelescopeNormal Normal
 
+" "Normal" in the preview floating windows created by telescope.
+highlight default link TelescopePreviewNormal Normal
+
 " Border highlight groups.
 "   Use TelescopeBorder to override the default.
 "   Otherwise set them specifically