Add Replace in... to context menus

Add "Replace in..." to project tree and working set context menus.

https://trello.com/c/3cKG28Fn/1309-replace-in-from-file-tree

cc @njx 

Nit: could we arrange these so the two identical ones are next to each other, rather than interleaved?  That makes it a little easier to spot that the two are the same.  (And actually we could even add a comment clarifying that we have two commands that do the same thing _only_ because we want different labels in different menus).