1. Update CSI constant to include the [ character.
See ECMA-48 Section 8.3.16
https://www.ecma-international.org/wp-content/uploads/ECMA-48_5th_edition_june_1991.pdf
2. Use string interpolation, because it's easier to read
(and internally uses a StringBuilder)
3. Add ESC constant, because the AnsiBuilder needs it to create links.
4. Remove unused SGR overload.
1. Add an ED3 command to clear the scroll buffer.
This command is not in the original ANSI terminal control sequences but
was added later to XTerm to account for the fact that most modern
terminals have a scroll-buffer.
https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h4-Functions-using-CSI-_-ordered-by-the-final-character-lparen-s-rparen:CSI-Ps-J.1C8A
This command is now awailable in basically
all terminals with scroll-buffers
2. Change CUP coordinates to 1, 1
The coordinates 0, 0 also worked, but strictly speaking they are outside
the available screen area and are capped to 1, 1 anyways.
This commit fixes#337
Christian WischenbartandPatrik Svensson
