add escape_html to readme

Author: L3P3

README.md

@@ -117,6 +117,7 @@ in both file types (dynamic served and services), you can use all node/bun metho
   - `async data_load(path)`: reads the file in data directory and returns its content or null
   - `async data_load_watch(path, callback(content))`: executes callback first and on every change
   - `async data_save(path, content)`: writes the content to the file in data directory
+  - `escape_html(str)`: escapes html special characters
 
 ## environment variables
 - `rtjscomp_path_data`: path to data directory, default is `./data`