If you double-click on the opcode of "JSR label", the code view
selection jumps to the label. This now works for partial operands,
e.g. "LDA #<label".
Some changes to the find-label-offset code affected the cc65 "is it
a forward reference to a direct-page label" logic. The regression
test now correctly identifies an instruction that refers to itself
as not being a forward reference.