The docs do not adequately explain the validate_cmd parameters

[jcbollinger]

Requested change

Please update the documentation for concat::concat::validate_cmd and concat_file::validate_cmd to provide sufficient details for users to use it successfully. That could be by copying the docs of File::validate_cmd or by inserting a reference to those docs, for example.

Context / explanation

With the current docs, users have to figure out that

• the designated command is expected to accept a file name string;
• a % character must be included in the command string as a placeholder for the filename;
• the command name in the string must be an absolute pathname; and
• the command is expected to exit with status 0 to indicate validity, and non-zero to indicate invalidity.

It might be reasonable to expect advanced Puppet users to guess some of that, but why should anyone need to guess? Or to study the module source to figure it out, which is what I had to do?