fix: use ; as engine separator

Signed-off-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

pkg/syntax/expression/expression.go

@@ -8,7 +8,7 @@ var (
 	foreachRegex = regexp.MustCompile(`^~(\w+)?\.(.*)`)
 	bindingRegex = regexp.MustCompile(`(.*)\s*->\s*(\w+)$`)
 	escapeRegex  = regexp.MustCompile(`^\\(.+)\\$`)
-	engineRegex  = regexp.MustCompile(`^\((?:(\w+):)?(.+)\)$`)
+	engineRegex  = regexp.MustCompile(`^\((?:(\w+);)?(.+)\)$`)
 )
 
 const (