fs/Path: add method GetSuffix()

Type-safe wrapper for uri_get_suffix().

src/TagFile.cxx

@@ -87,7 +87,7 @@ tag_file_scan(Path path_fs, const tag_handler &handler, void *handler_ctx)
 
 	/* check if there's a suffix and a plugin */
 
-	const char *suffix = uri_get_suffix(path_fs.c_str());
+	const char *suffix = path_fs.GetSuffix();
 	if (suffix == nullptr)
 		return false;