Addresses issue #2715

Send the correct line number.
If no N was in the command - non't send an N.

Replace the "ok" in M280, M301, M304, M851 with output not including an "ok"
to avoid senting two "ok"s for a single g-code.

Doing the same for M105 would break the input filters of the hosts.
For M105 the other "ok" is omitted.

Instead of changing SDEXTRASLOW variable to a slower speed,  the new
SDULTRASLOW is used for rigidbot panel.

Forgot Z2_MIN_PIN

Instead of changing SDEXTRASLOW variable to a slower speed,  the new
SDULTRASLOW is used for rigidbot panel.

• Removing trailing whitespace
• Adjusting indention for better readability
• Removing duplicated entries

//100k 0603 SMD Vishay NTCS0603E3104FXT (4.7k pullup) (calibrated for Makibox hot bed)

Caveat Emptor —- 
I’m not sure that this really makes sense,
but why keep someone from using it?

For some reason that I cannot determine, using a sub-function causes
the Tune sub-menu to act strangely, yet replacing the function call
with its code content works perfectly.