src/tool_vms.c: remove duplicated word in comment

Closes #6881
diff --git a/src/tool_vms.c b/src/tool_vms.c
index 18d20e7..efa933a 100644
--- a/src/tool_vms.c
+++ b/src/tool_vms.c
@@ -41,7 +41,7 @@
 
 static int vms_shell = -1;
 
-/* VMS has a DCL shell and and also has Unix shells ported to it.
+/* VMS has a DCL shell and also has Unix shells ported to it.
  * When curl is running under a Unix shell, we want it to be as much
  * like Unix as possible.
  */