Use M70 to set label for the filament to load at the M600 Insert filament screen

[Panayiotis-git]

A variation of the #4548. It repurposes the unused M70 command in the Prusa firmware to store a custom message, which is displayed by the M600 command on the load filament screen.

M70 Deep Blue
M600

The Insert filament screen will then show the custom text defined with the M70 command:

Insert filament
Deep Blue
and press the knob

[github-actions]

All values in bytes. Δ Delta to base

Target	ΔFlash	ΔSRAM	Used Flash	Used SRAM	Free Flash	Free SRAM
MK3S_MULTILANG	300	21	248122	5674	5830	2518
MK3_MULTILANG	302	21	247438	5683	6514	2509

[gudnimg]

Hi thanks for the PR. The only problem I see (at least on Github) is inconsistent indentation changes in the code. I commented on only two of them but there are more.

It could be a mix between spaces and tabs that makes the rendering different on Github.

[Panayiotis-git]

Something is really off...

I will resubmit the PR.

[gudnimg]

Much better, thanks!

[gudnimg]

Code looks good to me. I don’t see how it can go wrong. Should be tested on hardware though before merging, just in case.

[gudnimg]

I tested this on my MK3S+ and I didn't find any way to break things :)

• Sending only M70 shows no message ✔️
• Sending M70 "Hello World" shows "Hello World" including the " characters ✔️ Exactly like M117
• Running M600 the 2nd time (but not M70), no message is shown indicating it's reset properly. ✔️
• Sending M70 with a very long string (more than 20 characters) is truncated correctly to the LCD line limit. ✔️

If no one objects to this PR, I would like to merge it.

[3d-gussner]

Closing in favor of #4759