Test, validate and match regular expressions
Matches a square-bracketed tag (optionally containing slash-delimited paths and a short word prefix) followed by optional whitespace/newlines, then a double-curly-brace template expression supporting nested {{...}} blocks up to 11 levels deep, with optional /path/ segments inside. Useful for parsing custom markup combining bracketed shortcodes with Mustache/Handlebars-style templating, such as CMS content extraction or wiki syntax processing, using global matching.