Codechange: Pass encoded script strings as EncodedString.

This removes the ambiguity of having std::strings that may or may not be encoded.

src/strings_type.h

@@ -114,6 +114,11 @@ private:
 	explicit EncodedString(std::string &&string) : string(std::move(string)) {}
 
 	friend EncodedString GetEncodedStringWithArgs(StringID str, std::span<const StringParameter> params);
+
+	template <typename Tcont, typename Titer>
+	friend class EndianBufferWriter;
+	friend class EndianBufferReader;
+	friend class ScriptText;
 };
 
 #endif /* STRINGS_TYPE_H */