Add support for Asciidoc

[rlemaitre]

This implements issue #73: provide the choice of the file format when initialising ADR log.

I added the -t option to adr init that stores in the .adr-file-type file the chosen format (markdown by default). Format values can be md for Markdown or adoc for AsciiDoc.

I duplicated all tests (except the one that checks a title is given to adr new) to ensure AsciiDoc is managed properly.

I didn't managed hybrid logs (containing MarkDown and AsciiDoc), nor migration from MarkDown to AsciiDoc. The migration could be handled via documentation by creating manually .adr-file-type file and running Kramdoc or Pandoc.

My bash is far from perfect, can anyone look at this PR?

Thanks

[devth]

Would love to see this merged!

[sakirtemel]

Hi, any updates on this? This would work great with Antora and Arc42 if this gets merged (similar to here https://github.com/anoff/antora-arc42/tree/master/docs/modules/adr/pages )

[rlemaitre]

I was wondering, too. I'm more and more thinking about writing my own tool

[silopolis]

Things start looking like abandonware 😔

[baibaratsky]

Hello, @npryce!
Can we do anything to help this PR get merged? Please let us know if you have any doubts or suggestions.
If you don’t feel like adding support for AsciiDoc, please clearly decline this PR so we can start a separate project.