Version 0.28.6

Fixed

General TextEdit fixes for code refactoring:

• Update fix from 0.28.5 so that it doesn't pad at the start; no opcode will refer to old[-1:n].
• Revert opcode.old_end -> opcode.old_end - 1. This becomes unnecessary with prior update, and indeed could be a bad idea when in the middle of a file (if you're unlucky, you could end up finding the line before the one you wanted).
• Use pygls.document to get the old code, rather than the private jedi method.