Unmatched line is NOT ignored on right-justification mode. However this
commit makes such a line ignored when the end of the line is highlighted
as one of the ignored syntax groups (e.g. Comments or Strings)
- Preserve indentation when a line starts with a delimiter
- Useful for aligning multi-line method chains
- Renamed `margin_{left,right}` to `{left,right}_margin
- Makes it easier to type in (`l`, `r`)
- `margin_{left,right}` is still supported
- Margins can be specified as the number of spaces, or as an arbitrary string