build/win32/replace.py: Add Note On Its Reusability
build/win32/replace.py: Add Note On Its Reusability

Add a note stating that this script can be copied for use to replace
strings in files when necessary, such as replacing autotools variables
in non-autotools builds, such as Visual Studio builds.

tchakabam/glib,johne53/MB3Glib,MathieuDuponchelle/glib,endlessm/glib,tchakabam/glib,tchakabam/glib,tchakabam/glib,johne53/MB3Glib,cention-sany/glib,MathieuDuponchelle/glib,johne53/MB3Glib,endlessm/glib,tchakabam/glib,endlessm/glib,ieei/glib,cention-sany/glib,mzabaluev/glib,endlessm/glib,mzabaluev/glib,mzabaluev/glib,Distrotech/glib,Distrotech/glib,johne53/MB3Glib,cention-sany/glib,Distrotech/glib,ieei/glib,cention-sany/glib,Distrotech/glib,johne53/MB3Glib,Distrotech/glib,MathieuDuponchelle/glib,ieei/glib,MathieuDuponchelle/glib,johne53/MB3Glib,endlessm/glib,mzabaluev/glib,ieei/glib,mzabaluev/glib,MathieuDuponchelle/glib,ieei/glib,cention-sany/glib