system: add note to deprecate sstring

Signed-off-by: Simon Rozman <simon@rozman.si>

include/stdex/system.hpp

@@ -58,6 +58,8 @@ namespace stdex
 	///
 	/// Character type for system functions
 	///
+	/// \note TODO: Should migrate to std::filesystem::path::value_type. Research UNICODE/_UNICODE behavior on Windows.
+	///
 #if defined(_WIN32)
 	using schar_t = TCHAR;
 #else
@@ -73,6 +75,8 @@ namespace stdex
 	///
 	/// String for system functions
 	///
+	/// \note TODO: Should migrate to std::filesystem::path. Research UNICODE/_UNICODE behavior on Windows.
+	///
 	using sstring = std::basic_string<stdex::schar_t>;
 
 #ifdef UNICODE