Fix LaTeX rendering of strong next

Fix #597.

* spot/tl/print.cc: Fix rendering of X[!].
* doc/tl/spotltl.sty: Add a \StrongX definition.
* tests/core/latex.test: Add a test case.
* NEWS: Mention the issue.

NEWS

@@ -5,6 +5,9 @@ New in spot 2.12.1.dev  (not yet released)
   - to_finite() was dealing incorrectly with edges that were
     both alive and dead.  (Issue #596.)
 
+  - LaTeX output of the X[!] operator with broken in both
+    LaTeX and self-contained LaTeX mode.  (Issue #597)
+
 New in spot 2.12.1  (2024-09-23)
 
   Bug fixes:

doc/tl/spotltl.sty

@@ -12,6 +12,7 @@
 \newcommand{\F}{\mathsf{F}} % eventually
 \newcommand{\G}{\mathsf{G}} % always
 \newcommand{\X}{\mathsf{X}} % next
+\newcommand{\StrongX}{\mathsf{X^{[!]}}} % strong next
 % The \mathbin tells TeX to adjust spacing for binary operators
 \newcommand{\M}{\mathbin{\mathsf{M}}} % strong release
 \newcommand{\R}{\mathbin{\mathsf{R}}} % release

spot/tl/print.cc

@@ -318,7 +318,7 @@ namespace spot
       "^{=",
       "^{\\to",
       "\\mathsf{first\\_match}",
-      "\\textcircled{\\mathsf{X}}",
+      "\\mathsf{X^{[!]}}",
     };
 
     static bool

tests/core/latex.test

@@ -37,6 +37,7 @@ a U b W c R (d & e) M f
 {a*;(b;c)[:*3..4];(c;d)[:+];d}!
 G(uglyname->Fuglierlongname42)
 "#foo/$bar$" U "baz~yes^no"
+X[!]XX[!]a | G[2:4!]b
 EOF
 
 (