[NTOS:KDBG] Fix the ANSI escape sequences used to get terminal characteristics when printing with paging.
- Line-wrapping is enabled with 'ESC[?7h' (the '?' was forgotten).
Notice that the following reference also shows it wrong:
https://www.cse.psu.edu/~kxc104/class/cse472/09s/hw/hw7/vt100ansi.htm
- Terminal type is actually queried with 'ESC Z' (VT52-compatible), or
with 'ESC[c' (VT100-compatible). The antediluvian CTRL-E ('\x05')
control code gives instead a user-configurable (usually empty) string,
so it's not reliable.
Also, we don't really care about the returned result, we just need to
know that one has been sent.
Cross-checked with online documentation:
* "Digital VT100 User Guide" (EK-VT100-UG-001) (1st edition, August 1978,
reviewed November 1978).
* https://www.real-world-systems.com/docs/ANSIcode.html
* https://geoffg.net/Downloads/Terminal/TerminalEscapeCodes.pdf
* https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
* https://en.wikipedia.org/wiki/Enquiry_character
- Retrieve the size of the *controlling terminal* with escape sequences
only when it's a serial one: serial output is enabled *and* KDSERIAL
is set (i.e. user input through serial). See code for the actual logic
(the corresponding truth table is left as an exercise for the reader).
- Fix also a "Buffer" vs. "InBuffer" mismatch, that caused the whole
code to fail.
- For fallback terminal size values, use meaningful ones when SCREEN
is instead the controlling "terminal" (based on full-size BOOTVID
values).
- When echoing read characters during line-cooking, do direct output by
using KdpDprintf() instead of going through the heavy KdbpPrint() function.
This fixes some input artifacts like: 1. extra slowdowns due to
querying terminal size at each keypress, and 2. getting obnoxious
"--- Press q to abort ..." prompts in the middle of typing a long
comamnd because you are at the very bottom of the screen.