Reference manuals for m16c

[esaulenka]

Could you advice which documenation are you used to make this (probably, will be better to specify it in the README).

I found only one good manual: https://www.renesas.com/us/en/document/mah/m16c60-m16c20-m16ctiny-series-software-manual?r=1053161

[BitBangingBytes]

I added the software manual in my fork and a m16c.idx file to link all the instructions to the manual for use within Ghidra (Right click, Processor Manual) when selecting an instruction.