Small Fixes

• Bundle qt5ct in Linux for native look support;
• Use Return or Enter to confirm selection in macOS (besides Cmd+O);
• Support sync note list to current note automatically via config global/sync_note_list_to_current_tab Issue;
• Add Ctrl+E N to view and edit current note's information;
• Fix Markdown highlighter to handle fenced code block without a leading empty line;
• Prompt for restart after changing theme.