XML start/end tags

[sfkleach]

Support <foo ATTRS> ... </foo> and <bar ATTRS />

Monogram

• Create branch
• Add decision record
• Update grammar
• Update documentation
  • README
  • Change log
• Raise PR
• Respond to code review
• Merge into main

Monogram-Go

• Create branch
• Implement start/end tags
• Implement standalone tags
• Alter AST
• Add unit tests
• Add functional tests
• Update documentation
  • CHANGELOG
• Raise PR
• Respond to code review
• Merge into main