docs: Document ways of debugging homebrew.

[asiekierka]

In roughly this order:

• NO$GBA console output
• -lnds9d/-lnds7d
• sassert()
• melonDS GDB server
• NO$GBA debugger

[AntonioND]

I've added a new page about this:

https://github.com/blocksds/sdk/commit/6e9dd25b12dd54c85607dd35843ee6eac0afc913

https://blocksds.github.io/docs/usage/debugging/

This is still missing a section about how to use GDB to debug with melonDS.

[AntonioND]

I've also made assert() work on both the ARM9 and ARM7 work: https://github.com/blocksds/libnds/commit/bf3ef5be198a7e9e1c084ed5e4ace4307cb8a6e2

[AntonioND]

We need to mention the stack protector too.

EDIT: Added here: https://github.com/blocksds/sdk/commit/46dd429d42d79ba9584070d9e28dcb75eb1a828f

[AntonioND]

And this adds the last section, GDB with melonDS I haven't bene able to get it to work, I will try again later, but this is the general idea: https://github.com/blocksds/sdk/commit/d0974d093cad023a111b5949c37779d3c0a56cf3

[AntonioND]

I've also tried GDB debugging with DeSmuME, and that works: https://github.com/blocksds/sdk/commit/2978d5f39ef0c123e1931c9d82330931cfa3cc68