[LyX/master] Fix warning

[Richard Kimberly Heck]

commit d815f382fab232a05ec44d5a54090d53e180a90a
Author: Richard Kimberly Heck <rikiheck at lyx.org>
Date:   Thu Jul 27 16:56:48 2023 -0400

    Fix warning
---
 src/BiblioInfo.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/BiblioInfo.cpp b/src/BiblioInfo.cpp
index b7ec2b8..7c15cdd 100644
--- a/src/BiblioInfo.cpp
+++ b/src/BiblioInfo.cpp
@@ -379,7 +379,7 @@ docstring convertLaTeXCommands(docstring const & str)
 		}
 
 		if (ch == '~') {
-			ret += 0x00a0;
+			ret += char_type(0x00a0);
 			val = val.substr(1);
 			continue;
 		}