Reverts F5/F6/F8 from operating on current line (TLC extension) to MC behavior: do nothing when no selection is active. MC's eval_marks returns false when mark1==mark2, so F5/F6/F8 in MC are no-ops without a selection.
Removes the now-dead copy_line/cut_line/delete_line_no_sel helpers and their tests. Replaces with MC-parity no-op tests.
Extracts current_line_range() helper from select_current_line and duplicate_line_or_selection (also covers unindent_selection pattern). Removes ~50 lines of duplicated line-range computation.
vasilito
7d5b4088a6