ENGINES: Fix autosave name check (#3648)

The length of the German translation for Autosave is 23 characters. Save names in Groovie are limited to 15 characters, and it's probably not the only engine with a similar limit. This meant you would get a warning on every autosave, even though you just told it to overwrite. Mminimum of 14 characters for confidence that the name is a match and not a false positive.

engines/savestate.cpp

@@ -95,7 +95,16 @@ bool SaveStateDescriptor::isAutosave() const {
 
 bool SaveStateDescriptor::hasAutosaveName() const
 {
-	return _description.contains(_("Autosave"));
+	const Common::U32String &autosave = _("Autosave");
+
+	// if the save file name is long enough, just check if it starts with "Autosave"
+	if (_description.size() >= autosave.size())
+		return _description.substr(0, autosave.size()) == autosave;
+
+	// if the save name has been trimmed, as long as it isn't too short, use fallback logic
+	if (_description.size() < 14)
+		return false;
+	return autosave.substr(0, _description.size()) == _description;
 }
 
 bool SaveStateDescriptor::isValid() const