How exhaustively search emacs-help-info (including third-party-packages' info)

When strike "C-h d" which invoke "apropos-documentation" , it could exhaustively search target through all emacs help infos: Try search (map as instance: https://preview.redd.it/ncezret7skv81.png?width=947&format=png&auto=webp&s=2c0d9826acac22b11de176b80051e222e4f5db43 while I installed "dash" package and it displays from "C-h i": https://preview.redd.it/ry8cw41jskv81.png?width=833&format=png&auto=webp&s=8bd9f662117cd8bccdcf589497e7d6b9114dcd08 However, it fails to get dash.info included to search through. Try to search "(-map), it report no apropos matches. https://preview.redd.it/166fqa6vskv81.png?width=725&format=png&auto=webp&s=5bbf05b29313777fee2538a4c1678e602e9cc6bb How could get the third party infos included?

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You can search *everything* by going to the info manual top-level heading and doing `regexp-search-forward` (normally bound to `C-M-s`).

thank you and so impressive.