; Merge from origin/emacs-27

The following commits were skipped:

e79e377a4e (origin/emacs-27) Improve documentation of 'read-regexp' a...
0340e9eccb read-regexp-suggestions doc string improvement
932aba674c Try to improve the read-regexp doc string
809503431d ; xref-revert-buffer: Drop the (goto-char) at the end
0399cc2ab5 Erase the buffer only after fetching the new contents