[CHANGES]

• Internal XS-level changes:
  
  • Generate the basic accessor ops directly before invoking the
    gen_accessor_ops chain, ensuring more reliable ordering
    
  • Renamed the post_initfields field hook to post_makefields to
    better reflect when it actually runs
    
• Removed the special-case warning about method BUILD
  
• Added docs to point out that ADJUST blocks see method-like field
  lexicals