style: Remove vertical line separator after line numbers

src/main_ncurses.cpp

@@ -972,7 +972,7 @@ private:
             
             // Line number (if enabled)
             if (show_line_numbers) {
-                mvprintw(y + screen_y, x, "%3zu │ ", buffer_line_idx + 1);
+                mvprintw(y + screen_y, x, "%3zu   ", buffer_line_idx + 1);
             }
 
             // Line content with syntax highlighting