RFR: 8251551: Use .md filename extension for README

[Magnus Ihse Bursie]

On 2020-08-14 13:57, Erik Helin wrote:
> On 8/14/20 11:43 AM, Magnus Ihse Bursie wrote:
>> When I wrote the original README, the only use-case I had in mind was 
>> for someone to have checked out the code locally, not someone seeing 
>> it as a project description on Github. So I'd suggest a change more 
>> along these lines:
>> ---
>> For build instructions, please see the [online 
>> documentation](https://openjdk.java.net/groups/build/doc/building.html), 
>> or either of these files:
>>
>>   - [doc/building.html](doc/building.html) (html version)
>>   - [doc/building.md](doc/building.md) (markdown version)
>> ---
>
> Thanks for reviewing Magnus! I agree with your suggestion, please see 
> updated webrevs below:
>
> - full: https://cr.openjdk.java.net/~ehelin/8251551/01/
> - incremental: https://cr.openjdk.java.net/~ehelin/8251551/00-01/

Purrrr-fect! :)

Thanks for doing this.

/Magnus
>
> You can also see a rendered version of the README.md file in my 
> personal fork [0].
>
> Thanks,
> Erik
>
> [0]: https://github.com/edvbld/jdk/blob/readme/README.md