add THIS_LINE motion and MOTION_COUNT

src/core/Command.h

@@ -49,6 +49,7 @@ public:
         SCROLL_WINDOW_DOWN_HALF_SCREEN,
         SCROLL_WINDOW_UP_WHOLE_SCREEN,
         SCROLL_WINDOW_DOWN_WHOLE_SCREEN,
+
         COMMAND_COUNT,
     };
 
@@ -62,6 +63,12 @@ public:
             FORWARD_ON_TO_CHAR,
             BACK_UP_TO_CHAR,
             BACK_ON_TO_CHAR,
+
+            /* These motions aren't command-mode sequences but are used
+             * internally. */
+            THIS_LINE,
+
+            MOTION_COUNT,
         };
     };