cex: rename -Wcounterexample as -Wcounterexamples, and support -Wcex

Plural vs. singular is always a problem...

But we already have conflicts-sr and conflicts-rr, so counterexamples
makes more sense than counterexample.  Besides, -Wcounterexample will
still be accepted as an unambiguous prefix of -Wcounterexamples.

Add -Wcex as a convenient alias.

While at it, use only "counterexample", never "counter example".

* src/complain.h, src/complain.c
(Wcounterexample, warning_counterexample): Rename as...
(Wcounterexamples, warning_counterexamples): these.
(argmatch_warning_docs): Rename -Wcounterexample as -Wcounterexamples.
(argmatch_warning_args): Likewise.
Add support for -Wcex.
Adjust dependencies.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index 30e3ca69..5dd54d34 100644
--- a/src/main.c
+++ b/src/main.c
@@ -145,7 +145,7 @@ main (int argc, char *argv[])
       conflicts_update_state_numbers (old_to_new, nstates_old);
       free (old_to_new);
     }
-  if (warning_is_enabled (Wcounterexample))
+  if (warning_is_enabled (Wcounterexamples))
     counterexample_init ();
   conflicts_print ();
   timevar_pop (tv_conflicts);