bug#12526: 24.2.50; `query-replace-interactive' not always respected

[Drew Adams]

FWIW, in my local version, `query-replace-read-(from|to)' provides defaults (in
order):

a. The secondary selection, if option `search/replace-2nd-sel-as-default-flag'
is non-nil.

b. Using the (function) value of option `search/replace-default-fn'.  This is a
thing-at-point function such as `non-nil-symbol-name-nearest-point' or
`word-at-point'.  If it returns a list of values then they are all available as
defaults.

c. Using `completing-read', if option `replace-w-completion-flag' is non-nil,
with default `query-replace-from-history-variable'.

d. The usual way, from the history list.

That gives the user a fair number of choices.