Document the .messages file format.

TODO

@@ -19,17 +19,10 @@
   This would allow some simplifications in CompCert's grammar.
 
 * Document --list-errors --interpret-error --compile-errors --compare-errors --update-errors --echo-errors %on_error_reduce
-    explain that any production that contains [error] is ignored by --list-errors
-  document the .messages file format
-    likely pitfall: if Menhir says, "foo" is not a valid nonterminal symbol,
-    then look for a blank line, higher up, between two sentences.
-    explain the meaning of the spurious reductions warning (sometimes missing!)
-    --compile-errors could warn about messages wider than 80 columns
-    --on-error-reduce should warn about arguments which are not names of terminal symbols
-      and should remove any spaces in the names!
-    could also warn statically about out-of-range $i?
-  document the workflow
-  --interpret-error obeys --trace
+  --compile-errors could warn about messages wider than 80 columns
+  --on-error-reduce should warn about arguments which are not names of terminal symbols
+    and should remove any spaces in the names!
+  could also warn statically about out-of-range $i?
 
 * Dans les avantages de Menhir versus ocamlyacc (dans la doc et
   sur la page Web), ajouter le back-end Coq, l'API incrémentale

doc/local.bib

@@ -4,3 +4,13 @@
   year         = "2014",
   howpublished = "\url{https://github.com/AbsInt/CompCert}",
 }
+
+@Unpublished{pottier-reachability,
+  author =       {François Pottier},
+  title =        {Reachability and error diagnosis in LR(1) automata},
+  note =         {Submitted for publication},
+  month =     oct,
+  year =      2015,
+  URL =    {http://gallium.inria.fr/~fpottier/publis/fpottier-reachability.pdf}
+}
+