[plt-translators] english-string-constants.rkt update

Philippe Meunier wrote:
>- (mfs-drscheme-multi-file-search "DrRacket - Multi File Search") ;; results window and error message title
>+ (mfs-drscheme-multi-file-search "Multi File Search - DrRacket") ;; error message window title

Note that Robby has already done this change in all the translation
files, not just english-string-constants.rkt.

>- 
>+ (mfs-drscheme-multi-file-search-title "Multi File Search for \"~a\" - DrRacket") ;; the ~a format specifier is filled in with the search string
>+  

This one is new though.

Philippe