fix github issue #1250 and #1229 - ^A issues

Reported by ars3nly as "#1250: Repeating #sit causes a sitting loop",
with a followup comment describing how to reproduce easily, and by
Umbire as "#1229: Curses and extended command menus".  Repeat count
from previous command carried over to current command when ^A was
used to re-run the current one.

Reset 'last_command_count' every time a repeat count is obtained,
even when the new one is 0.  This is a much simpler fix than what
was used with several previous attempts, but it seems to be working.

The do-again code is convoluted, but the tricky bit was the fact
that this problem only happened when number_pad was On with repeat
counts entered as 'n<digits>'.  I still don't understand that aspect,
but it wasn't happening for count of simple '<digits>', making
reproducing it by someone who doesn't use number_pad be difficult....

Closes #1229
Closes #1250

src/cmd.c

@@ -4743,8 +4743,8 @@ parse(void)
 
         foo = get_count((char *) 0, '\0', LARGEST_INT,
                         &gc.command_count, GC_NOFLAGS);
-        gl.last_command_count = gc.command_count;
     }
+    gl.last_command_count = gc.command_count;
 
     if (foo == gc.Cmd.spkeys[NHKF_ESC]) { /* esc cancels count (TH) */
         clear_nhwindow(WIN_MESSAGE);