- "Double quotes" for strings (filenames, section names, CLI option arguments, etc)
- 'Single quotes' for characters and CLI option flags
- `Backticks` for keywords and identifiers (symbol names, charmap names, etc)
CLI option flags also have their leading dashes
`Expansion::advance()` can increase its offset beyond the size,
so I don't think this assumption was valid in the first place;
`BufferedContent::advance()` should be able to as well.