Don't allow multiple sections with the same path

[SmileyChris]

Each section needs a unique path for towncrier to correctly pick up and build news fragments for that section.

It could be a good improvement to error out if the configuration file has multiple sections with the same path (even if that path is "").

[adiroiban]

Thanks for the follow up.

I think that as part of this work, we should also document the "default section" , in the configuration documentation where sections are mentioned

I can be:

• the section without a path
• if all sections have path, the first one defined is the default.

[SmileyChris]

Fixed