* Improve 'vttest' scenarios:
1. Report terminal as VT220 with sixel rather than VT400 family with
sixel. This fixes a hang when launching vttest as it is waiting for
a response to DECRQSS.
2. Test 6.2: Support NewLine mode (CR --> CRLF).
3. Test 6.3: Fix DSR cursor position report to honor scrolling region.
4. Test 6.7: Parse and respond to DECREQTPARM (Request Terminal
Parameters - CSI x). This is a VT100 sequence that xterm used to
respond to always, but more recently only responds to when
explicitly set to VT100 level.
* cargo fmt
* Fix failing unit test snapshot
* fix clippy error
* VT100 UK character set
a316577d1e