addTextFilePage function
Implementation
void addTextFilePage(String stdout, List<Widget> pages) {
String content = rExtract(stdout, '> cat(txt,');
String title = '''
# Text Content
Generated using
[base::cat(txt)](https://www.rdocumentation.org/packages/base/topics/cat).
''';
if (content.isNotEmpty) {
pages.add(TextPage(title: title, content: '\n$content'));
}
}