Shared search for values on 'Find' / 'Replace' / 'Find in files'

[chrisgraham]

I think all these 3 dialogs should share the same 'search for' value and history.

For example, if I do a search for 'foo' and then decide I want to do a replace of 'foo' with 'bar', it would be good if the replace dialog had 'foo' in there already.
(I realize if I leave the last search result highlighted it would, but I may not do so)

This issue may relate to the implementation of #1666.

[elextr]

Probably needs internal implementation of FIF since its options are wildly differing, but also there are differing options on find and the findy part of replace that would need resolving to ensure you get the same result for a common search pattern.