[LyX/master] ctests: extend regression test for #13004

[Scott Kostyshak]

commit 367a4be425b4dbdaef5d0cfdbdf9ea97228d52fb
Author: Scott Kostyshak <skostysh at lyx.org>
Date:   Sun Sep 14 11:29:27 2025 +0200

    ctests: extend regression test for #13004
    
    This case was fixed by 55f10d7f.
---
 .../export/latex/lyxbugs-resolved/13004-double-superscript.lyx     | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/autotests/export/latex/lyxbugs-resolved/13004-double-superscript.lyx b/autotests/export/latex/lyxbugs-resolved/13004-double-superscript.lyx
index 00ceabdd1c..09cb1b28b9 100644
--- a/autotests/export/latex/lyxbugs-resolved/13004-double-superscript.lyx
+++ b/autotests/export/latex/lyxbugs-resolved/13004-double-superscript.lyx
@@ -82,6 +82,13 @@
 \end_inset
 
 
+\end_layout
+
+\begin_layout Standard
+\begin_inset Formula $x'_{n}'$
+\end_inset
+
+
 \end_layout
 
 \end_body