Feature Request: Allow help texts for menu options

[matthijskooijman]

Currently, menu options can be specified for boards, to make "subselections" of a given board or set other options. Since these menus are currently used for sometimes quite complex and non-selfexplanatory choices (e.g. the USB stack to use in the Adafruit SAMD core, the partitioning scheme in the ESP32 core, etc.), it would be helpful if platforms could provide some help texts for each option (note that some of these options should not really be board-specific but global, see #922 about that).

These help texts could then be displayed in the arduino-cli board detail output, or in the Java IDE menus (as a tooltip, or maybe a separate "help" item in the menu maybe).

As an example, this could look like this:

menu.cpu=Processor

mini.name=Arduino Mini
mini.menu.cpu.atmega328=ATmega328P
mini.menu.cpu.atmega328.build.mcu=atmega328p
mini.menu.cpu.atmega168=ATmega168
mini.menu.cpu.atmega168.build.mcu=atmega168
mini.menu.cpu.help=The Arduino Mini is available with different microcontroller chips. Older versions (sold before 201x) use the smaller ATmega168, while more recent versions use the bigger ATmega328p chip. You can tell which you have by closely examining the printing on the biggest chip on the board, or you can just try both options to see which works.

This could maybe look something like this:

matthijs@grubby:~$ arduino-cli board details arduino:avr:mini
Board name:             Arduino Mini
FQBN:                   arduino:avr:mini
Board version:          1.8.2
(...)

Option:                 Processor: The Arduino Mini is available with different microcontroller
                                   chips. Older versions (sold before 201x) use the smaller
                                   ATmega168, while more recent versions use the bigger ATmega328p
                                   chip. You can tell which you have by closely examining the
                                   printing on the biggest chip on the board, or you can just try
                                   both options to see which works.
                        ATmega328P                                            ✔ cpu=atmega328
                        ATmega168                                               cpu=atmega168