Fix classic Windows configuration for libexslt

As is, the `LIBEXSLT_DOTTED_VERSION` would be `@LIBEXSLT_VERSION@` when
using the classic Windows configuration (win32/configure.js).  This has
apparently been overlooked when exsltconfig.h.in has been changed a
while ago[1].

[1] <https://gitlab.gnome.org/GNOME/libxslt/-/commit/4045ed4b05bb400359d02ce6e9b0ca9b97c04750>

win32/configure.js

@@ -251,8 +251,8 @@
 	while (ofi.AtEndOfStream != true) {
 		ln = ofi.ReadLine();
 		s = new String(ln);
-		if (s.search(/\@VERSION\@/) != -1) {
-			of.WriteLine(s.replace(/\@VERSION\@/, 
+		if (s.search(/\@LIBEXSLT_VERSION\@/) != -1) {
+			of.WriteLine(s.replace(/\@LIBEXSLT_VERSION\@/, 
 				verMajorExslt + "." + verMinorExslt + "." + verMicroExslt));
 		} else if (s.search(/\@LIBEXSLT_VERSION_NUMBER\@/) != -1) {
 			of.WriteLine(s.replace(/\@LIBEXSLT_VERSION_NUMBER\@/,