patch 9.0.1594: some internal error messages are translated

Problem:    Some internal error messages are translated.
Solution:   Consistently do not translate internal error messages.
            (closes #12459)
diff --git a/src/if_tcl.c b/src/if_tcl.c
index 130e3e1..9e7cd4c 100644
--- a/src/if_tcl.c
+++ b/src/if_tcl.c
@@ -1552,7 +1552,7 @@
 	reflist = reflist->next;
     }
     // This should never happen.  Famous last word?
-    iemsg(_(e_tcl_fatal_error_reflist_corrupt_please_report_this));
+    iemsg(e_tcl_fatal_error_reflist_corrupt_please_report_this);
     Tcl_SetResult(interp, _("cannot register callback command: buffer/window reference not found"), TCL_STATIC);
     return TCL_ERROR;
 }