Documentation clarification: Add link from endianess to unaligned_type

[denravonska]

I was looking at the Endian section to find fixed endian integers, but I later realized that they are located in unaligned_type. That makes sense when you know how they work, but it doesn't when you don't :)

Maybe it could be a good idea to add a note in Endian to point people in the right direction. Something like

If you are looking for fixed endian integers like le_int16_t or be_uint32_t you can find them in unaligned_type.

[jwellbelove]

Done