Fix exit code when history is not valid

[ligurio]

• Return non-zero exit code when history is not valid
• Fix indentation
• Print file path when file not found

[mprimi]

Thank you for the quick turnaround on this. Personally I like this, but notice this behavior is not what the README describes:

prints out the names of all files you asked it to check, followed by a tab, and then whether the history was valid.

Could update the README to say "terminates at the first non-valid", or could still run all of them and return non-zero if any of them is non-valid.

[ligurio]

Could update the README to say "terminates at the first non-valid", or could still run all of them and return non-zero if any of them is non-valid.

Patch has been updated, now it checks the whole list of histories and then exits.