[LyX/master] Fix make check

[Juergen Spitzmueller]

commit c219159530af2536b6827371c06d15d57d4db567
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Tue Feb 24 08:12:10 2026 +0100

    Fix make check
    
    This amends 29e73df9803
---
 lib/layouts/sn-jnl.layout | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/layouts/sn-jnl.layout b/lib/layouts/sn-jnl.layout
index b19571be82..aef6478e11 100644
--- a/lib/layouts/sn-jnl.layout
+++ b/lib/layouts/sn-jnl.layout
@@ -253,7 +253,7 @@ Style "Backmatter heading"
     NextNoIndent    1
     DocBookTag      bridgehead
     DocBookTagType  paragraph
-    DocBookAttr     role="backmatter"
+    DocBookAttr     role='backmatter'
 End
 
 Style Appendices