perl #82278: Overload documentation: many changes This is a partial rewrite to addres...

perl #82278: Overload documentation: many changes This is a partial rewrite to address long standing issues and comments that this document is confusing, in addition to accurately documenting the behaviour of fallback and nomethod in the context of overloaded operands of different types, as implemented in the fix for bug #71286. Fixes many mistakes, ambiguities, and omissions. Most of the early part of the document has been restructured and revised. For the full list of changes, see bug #82278.