fix: revert buffers previewer (#1400)

* Reverts #1120 many issues arise (mru, highlighting, settings inheritance, ...) when previewing actual buffers

lua/telescope/previewers/term_previewer.lua

@@ -274,6 +274,9 @@ previewers.vimgrep = defaulter(function(opts)
       if p == nil or p == "" then
         return
       end
+      if entry.bufnr and (p == "[No Name]" or vim.api.nvim_buf_get_option(entry.bufnr, "buftype") ~= "") then
+        return
+      end
 
       local lnum = entry.lnum or 0