* factor: emit GNU's 'X is not a valid positive integer' wording
GNU's factor.c routes both stdin and command-line input through the same
print_factors() and reports invalid input as
factor: 'X' is not a valid positive integer
Match that wording exactly so the new GNU 9.11 'nul4' test passes and
the 'cont' test no longer needs the warning/invalid-digit hunk in
tests_factor_factor.pl.patch.
* Add 'cmdline' to spell-checker ignore list
Sylvestre LedruandGitHub
b2c4e0c125