Add a command-mode mapping for ':' instead of handling it specially

src/core/Command.h

@@ -48,6 +48,7 @@ public:
         SCROLL_WINDOW_DOWN_HALF_SCREEN,
         SCROLL_WINDOW_UP_WHOLE_SCREEN,
         SCROLL_WINDOW_DOWN_WHOLE_SCREEN,
+        ENTER_COMMAND_LINE_PROMPT,
 
         COMMAND_COUNT,
     };