In incremental searches, a space or spaces normally matches any
whitespace defined by the variable `search-whitespace-regexp'.
To search for a literal space and nothing else, enter C-q SPC.
-To toggle whitespace matching, use `isearch-toggle-lax-whitespace'.
+To toggle whitespace matching, use `isearch-toggle-lax-whitespace',
+usually bound to `M-s SPC' during isearch.
This command does not support character folding."
(interactive "P\np")
(isearch-mode t (null not-regexp) nil (not no-recursive-edit)))