Strgen: Fix compiler warning in LangString constructor

src/strgen/strgen.h

@@ -40,7 +40,7 @@ struct LangString {
 	bool no_translate_mode = false;
 	LangString *default_translation = nullptr;
 
-	LangString(std::string name, std::string english, size_t index, int line);
+	LangString(std::string name, std::string english, int index, int line);
 	void ReplaceDefinition(std::string english, int line);
 	void FreeTranslation();
 };

src/strgen/strgen_base.cpp

@@ -50,7 +50,7 @@ Case::Case(int caseidx, std::string string) :
  * @param index   The index in the string table.
  * @param line    The line this string was found on.
  */
-LangString::LangString(std::string name, std::string english, size_t index, int line) :
+LangString::LangString(std::string name, std::string english, int index, int line) :
 		name(std::move(name)), english(std::move(english)), index(index), line(line)
 {
 }