[LyX/master] Fix gcc-12 warning

[Scott Kostyshak]

commit 725168baba0b1baba0b519a4069b88a08db5d239
Author: Scott Kostyshak <skostysh at lyx.org>
Date:   Sat Sep 24 14:24:26 2022 -0400

    Fix gcc-12 warning
    
    From Kornel:
    
    >  /usr2/src/lyx/lyx-git/src/Paragraph.cpp:1931:1: warning: control reaches end of non-void
    >  function [-Wreturn-type]
    >
    > This is with gcc-12, compiled in debug mode.
---
 src/Paragraph.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/Paragraph.cpp b/src/Paragraph.cpp
index 86e5b0e..4ce9441 100644
--- a/src/Paragraph.cpp
+++ b/src/Paragraph.cpp
@@ -1927,7 +1927,8 @@ FontSpan Paragraph::fontSpan(pos_type pos) const
 
 	// This should not happen, but if so, we take no chances.
 	LYXERR0("Paragraph::fontSpan: position not found in fontinfo table!");
-	LASSERT(false, return FontSpan(pos, pos));
+	LASSERT(false, /**/);
+	return FontSpan(pos, pos);
 }