[LyX/master] Fix copy&paste error

[Enrico Forestieri]

commit 968be3f2096e0faaa3c1ffa676e062992be3f0a6
Author: Enrico Forestieri <forenr at lyx.org>
Date:   Wed Mar 17 08:59:04 2021 +0100

    Fix copy&paste error
---
 src/frontends/qt/LaTeXHighlighter.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/frontends/qt/LaTeXHighlighter.cpp b/src/frontends/qt/LaTeXHighlighter.cpp
index d199fb1..453f98b 100644
--- a/src/frontends/qt/LaTeXHighlighter.cpp
+++ b/src/frontends/qt/LaTeXHighlighter.cpp
@@ -137,7 +137,7 @@ void LaTeXHighlighter::highlightBlock(QString const & text)
 		int length = match.capturedEnd(1) - index;
 		setFormat(index, length, mathFormat);
 		match = exprMath.match(text, index + length);
-		int index = match.capturedStart(1);
+		index = match.capturedStart(1);
 	}
 	// [ ]
 	static const QRegularExpression exprStartDispMath("(\\\\\\[|"