[LyX/master] Some comments into bind file

[Pavel Sanda]

commit de781a7cff034974f041be4457b2de2d8c9d3817
Author: Pavel Sanda <sanda at lyx.org>
Date:   Wed Jun 5 20:42:10 2024 +0200

    Some comments into bind file
---
 lib/bind/cua.bind | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/bind/cua.bind b/lib/bind/cua.bind
index c99a0c8da8..4dc6cc2568 100644
--- a/lib/bind/cua.bind
+++ b/lib/bind/cua.bind
@@ -26,6 +26,12 @@
 #
 # Happy tuning!
 
+# Note: modifiers on PC keyboards:
+# C - Ctrl
+# M - Alt
+# S - Shift
+#~S - Ignore shift (useful for numbers on localized keyboards)
+
 # Free bindings:
 
 #\bind "C-h"