PR changed files list & clickable filenames

[rakanalh]

It would be great if the package can also show the list of files that have been changed. Also the file names / hunks should be clickable to be able to navigate to the file's place of change quickly.

Edit: This is similar to what magit offers

[charignon]

To investigate this, I would start looking at patch support in magit and see if we can find a minor mode that would give us that kind of capabilities (folding a diff and navigate through it quickly):

• If such feature exists we can it enable in the case where the PR belongs to a repo checked out locally already (see https://github.com/charignon/greview/issues/1)
• If it does not exist, I would look at adding it to the magit mode for patches and leverage it here.

[yqrashawn]

Also it'll be great if the diff of hunks and files can be toggle between expanded and collapsed