Consider .adoc extension

[tomschr]

Situation

Currently, all the source files end with .txt.

Suggestion

Why not use .adoc as a file extension? This has some benefits:

• Small change, big impact.
• GitHub renders .adoc automatically when you open them on their web site.
• Easier to read than the raw source code.
• Supports your readers, they don't have to build the book.

Of course it won't be perfect, but nobody expects that. 😉

Example

https://github.com/SUSE/doc-susemanager/blob/master/modules/administration/pages/icinga.adoc