private static String getFileNameFromGistURL(String url) {
		StringBuilder fileName = new StringBuilder();
		String[] pathPlusAnchor = url.split("#");
		if (pathPlusAnchor.length == 2) {
			String[] anchor = pathPlusAnchor[1].split("-");
			if (anchor.length < 2)
				throw new IllegalArgumentException("Invalid Gist url: " + url);
			fileName = new StringBuilder(anchor[1]);
			for (int i = 2; i < anchor.length - 1; ++i)
				fileName.append("-").append(anchor[i]);
		}
		return fileName.toString();
	}
Takes common patterns and return "parent" urls that are meaningfull to trust.
i.e. github.com/maxandersen/myproject/myfile.java will offer to trust the
github.com/maxandersen/myproject project.

@param url
@return
src/main/java/dev/jbang/util/Util.java