msh: fix Ctrl-C handling with line editing

include/libbb.h

@@ -963,10 +963,9 @@ enum {
 };
 line_input_t *new_line_input_t(int flags);
 /* Returns:
- * -1 on read errors or EOF, or on bare Ctrl-D.
- * 0  on ctrl-C,
+ * -1 on read errors or EOF, or on bare Ctrl-D,
+ * 0  on ctrl-C (the line entered is still returned in 'command'),
  * >0 length of input string, including terminating '\n'
- * [is this true? stores "" in 'command' if return value is 0 or -1]
  */
 int read_line_input(const char* prompt, char* command, int maxsize, line_input_t *state);
 #else