Fix exception in repeated command function (#2038)

pwndbg/commands/__init__.py

@@ -172,7 +172,13 @@ class Command(gdb.Command):
 
         last_line = lines[-1]
         number_str, command = last_line.split(maxsplit=1)
-        number = int(number_str)
+        try:
+            number = int(number_str)
+        except ValueError:
+            # In rare cases GDB will output a warning after executing `show commands`
+            # (i.e. "warning: (Internal error: pc 0x0 in read in CU, but not in
+            # symtab.)").
+            return False
 
         # A new command was entered by the user
         if number not in Command.history: