doc: ltlcross is not only about Büchi anymore

* bin/man/ltlcross.x, doc/org/ltlcross.org, doc/org/tools.org: Fix
one-line summaries.

bin/man/ltlcross.x

 .\" -*- coding: utf-8 -*-
 [NAME]
-ltlcross \- cross-compare LTL/PSL translators to Büchi automata
+ltlcross \- cross-compare LTL/PSL translators to omega-automata
 [EXAMPLES]
 The following commands compare never claims produced by
 .BR ltl2tgba (1),

doc/org/ltlcross.org

@@ -3,7 +3,7 @@
 #+SETUPFILE: setup.org
 #+HTML_LINK_UP: tools.html
 
-=ltlcross= is a tool for cross-comparing the output of LTL-to-Büchi
+=ltlcross= is a tool for cross-comparing the output of LTL-to-automata
 translators.  It is actually a Spot-based clone of [[http://www.tcs.hut.fi/Software/lbtt/][LBTT]], the
 /LTL-to-Büchi Translator Testbench/, that essentially performs the
 same sanity checks.

doc/org/tools.org

@@ -43,7 +43,7 @@ corresponding commands are hidden.
 - [[file:genltl.org][=genltl=]] Generate LTL formulas from scalable patterns.
 - [[file:ltl2tgba.org][=ltl2tgba=]] Translate LTL/PSL formulas into Büchi automata.
 - [[file:ltl2tgta.org][=ltl2tgta=]] Translate LTL/PSL formulas into Testing automata.
-- [[file:ltlcross.org][=ltlcross=]] Cross-compare LTL/PSL-to-Büchi translators.
+- [[file:ltlcross.org][=ltlcross=]] Cross-compare LTL/PSL-to-automata translators.
 - [[file:ltlgrind.org][=ltlgrind=]] List formulas similar to but simpler than a given LTL/PSL
   formula
 - [[file:dstar2tgba.org][=dstar2tgba=]] Convert automata with any acceptance into variants of