Add replace-query action

replace-query action replaces the query string with the current
selection. If the selection is too long, it will be truncated.

If the line contains meta-characters of fzf search syntax, it is
possible that the line is no longer included in the updated result.

e.g.

  echo '!hello' | fzf --bind ctrl-v:replace-query

Close #1137

man/man1/fzf.1

@@ -525,6 +525,7 @@ triggered whenever the query string is changed.
     \fBpreview-page-up\fR
     \fBprevious-history\fR      (\fIctrl-p\fR on \fB--history\fR)
     \fBprint-query\fR           (print query and exit)
+    \fBreplace-query\fR         (replace query string with the current selection)
     \fBselect-all\fR
     \fBtoggle\fR                (\fIright-click\fR)
     \fBtoggle-all\fR