Don't bind search-spaces-regexp around possible autoload (Bug#35802)

* lisp/isearch.el (isearch-search-fun-default): Move possible autoload
trigger outside let-binding of search-spaces-regexp.
* lisp/char-fold.el (char-fold-make-table): Remove no longer needed
workaround.

* lisp/info.el (Info-search-whitespace-regexp):
* lisp/isearch.el (search-whitespace-regexp):
* src/search.c (syms_of_search) <search-spaces-regexp>: Add warning
about adding capturing groups to the value.

* test/lisp/char-fold-tests.el: Remove, binding search-spaces-regexp
to a different should be considered a bug.

1 files changed, 3 insertions, 1 deletions

diff --git a/lisp/info.el b/lisp/info.el
index f65c6c36272..8e8c3371f42 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -349,7 +349,9 @@ This only has an effect if `Info-hide-note-references' is non-nil."
 This applies to Info search for regular expressions.
 You might want to use something like \"[ \\t\\r\\n]+\" instead.
 In the Customization buffer, that is `[' followed by a space,
-a tab, a carriage return (control-M), a newline, and `]+'."
+a tab, a carriage return (control-M), a newline, and `]+'.  Don't
+add any capturing groups into this value; that can change the
+numbering of existing capture groups in unexpected ways."
   :type 'regexp
   :group 'info)