Match capstone immediate formatting in aarch64 disassembler

- Small values (< 10) use decimal: #7, #0
- Larger values use hex: #0x20, #0x1000
- Signed negatives: #-8, #-0x10
- Branch conditions use b.cond format: b.ne, b.eq
- Branch targets as absolute hex: #0x400
- Memory offsets use same decimal/hex convention
- movk shift uses comma separator: , lsl Shopify#16
- All immediates have # prefix

Author: tekknolagi