patch 8.0.0466: still macros that should be all-caps

Problem:    There are still a few macros that should be all-caps.
Solution:   Make a few more macros all-caps.
diff --git a/src/if_xcmdsrv.c b/src/if_xcmdsrv.c
index 6ef2335..fa91c3e 100644
--- a/src/if_xcmdsrv.c
+++ b/src/if_xcmdsrv.c
@@ -231,7 +231,7 @@
 	    if (res < -1 || i >= 1000)
 	    {
 		MSG_ATTR(_("Unable to register a command server name"),
-							      hl_attr(HLF_W));
+							      HL_ATTR(HLF_W));
 		return FAIL;
 	    }
 	    if (p == NULL)