hs-hide-all runs infinitely in *Ilist* buffer

[bmag]

After this commit, calling hs-hide-all in *Ilist* buffer runs infinitely and has to be stopped with C-g.

[markasoftware]

Change variable hs-hide-comments-when-hiding-all to nil.

Best: (add-hook imenu-list-major-mode-hook (lambda () (setq-local hs-hide-comments-when-hiding-all nil)))