Use wxSTC::GetTextRaw rather than converting utf-8 -> wxString -> utf-8

aegisub/src/scintilla_text_ctrl.cpp

@@ -52,7 +52,7 @@ int ScintillaTextCtrl::GetUnicodePosition(int pos) {
 
 /// @brief Reverse unicode-compatible position
 int ScintillaTextCtrl::GetReverseUnicodePosition(int pos) {
-	wxCharBuffer buffer = GetText().utf8_str();
+	wxCharBuffer buffer = GetTextRaw();
 
 	// Limit position to it
 	if (pos > (signed)buffer.length()) pos = buffer.length();

aegisub/src/subs_edit_ctrl.cpp

@@ -283,7 +283,7 @@ void SubsTextEditCtrl::SetStyles() {
 void SubsTextEditCtrl::UpdateStyle() {
 	StartStyling(0,255);
 
-	std::string text = STD_STR(GetText());
+	std::string text = GetTextRaw().data();
 
 	if (!OPT_GET("Subtitle/Highlight/Syntax")->GetBool()) {
 		SetStyling(text.size(), 0);