[CPP][Analyzers]Turn on warning 4244 (#22019)

* Turn on warning 4244

fix one occurrence of 4100

* changes from comments

* toupper on wchar

src/common/SettingsAPI/settings_objects.h

@@ -2,6 +2,8 @@
 
 #include "../utils/json.h"
 
+#include <cwctype>
+
 namespace PowerToysSettings
 {
     class HotkeyObject;
@@ -230,7 +232,7 @@ namespace PowerToysSettings
                 if (output_bytes == 1 && output[0] >= 'a' && output[0] <= 'z')
                 {
                     // Make Latin letters keys capital, as it looks better
-                    output[0] = toupper(output[0]);
+                    output[0] = std::towupper(output[0]);
                 }
                 return output.data();
             }