[Rev 02] RFR: Add checkout instructions to PR body

[Jorn Vernee]

> Hi,
> 
> I'd like let the pr bot add the fetch comamnd found in the automatic emails to the PR body, so that people using only GitHub can see the instructions as well.
> 
> This adds a new "Instructions" section to the body of the PR message:
> 
>> ## Instructions
>> To checkout these changes locally:
>> ```bash
>> $ git fetch https://git.openjdk.java.net/panama-foreign pull/16/head:pull/16
>> $ git checkout pull/16
>> ```
> 
> Testing:
> - Running `.\gradlew test`
> 
> Any other recommendations for testing this?
> 
> Thanks,
> Jorn

The pull request has been updated with 1 additional commit.

-------------

Added commits:
 - 93d02e60: Use markdown thematic break

Changes:
  - all: https://git.openjdk.java.net/skara/pull/434/files
  - new: https://git.openjdk.java.net/skara/pull/434/files/0774b382..93d02e60

Webrevs:
 - full: https://webrevs.openjdk.java.net/skara/434/webrev.02
 - incr: https://webrevs.openjdk.java.net/skara/434/webrev.01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/434.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/434/head:pull/434

PR: https://git.openjdk.java.net/skara/pull/434