[LyX/master] is_utf8 is always passed a char.

[Richard Kimberly Heck]

commit e8800373e6426c3ce9a3406d55067ca3612378ea
Author: Richard Kimberly Heck <rikiheck at lyx.org>
Date:   Sun May 3 15:02:25 2020 -0400

    is_utf8 is always passed a char.
---
 src/support/qstring_helpers.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/support/qstring_helpers.h b/src/support/qstring_helpers.h
index 45e0434..e33131c 100644
--- a/src/support/qstring_helpers.h
+++ b/src/support/qstring_helpers.h
@@ -41,7 +41,7 @@ QString toqstr(std::string const & str);
 
 
 /// Is \p c a valid utf16 char?
-inline bool is_utf16(unsigned int c)
+inline bool is_utf16(char_type c)
 {
 	// 0xd800 ... 0xdfff is the range of surrogate pairs.
 	return c < 0xd800 || (c > 0xdfff && c < 0x10000);