Add GitHub issues navigation for IDEA

[whyoleg]

Allows to click on issue/PR numbers in VCS history and be redirected to GitHub

Example:

Here on screenshot we can see Git window and 3 highlighted links: #3333 and #3327 in the left panel + #3333 in the right panel. All of them are clickable and will redirect to https://github.com/Kotlin/dokka/pull/3333 or https://github.com/Kotlin/dokka/pull/3327.

Why do we need this?

This simplifies a lot following Git Blame, and so understanding of context on why one or another change were implemented (via PR comments or issue description).
In last couple of days, while investigating behaviour of CodeBlocks I've done a lot of copy-pasting of issue number to GitHub and I was tired of this :) So I've configured this for local development.

Later I've found, that it's possible to share this config via Git, like in kotlinx-coroutines: https://github.com/Kotlin/kotlinx.coroutines/blob/ecb5b3e1e3c94cf377b9b3d21a8ad455bc83f0d0/.idea/vcs.xml#L13.
PR in coroutines: Kotlin/kotlinx.coroutines#1920
And so here we are

P.S. If possible, please check, that after fetching this branch, changes are applied at your side. I have not added vcs.xml to .gitignore for a reason: it can contain other settings, which we are not interested in

[IgnatBeresnev]

👍 👍

I've checked out the branch, and I can see the changes, but I haven't done any additional testing

[vmishenev]

I have not added vcs.xml to .gitignore for a reason: it can contain other settings, which we are not interested in

After VCS enabling, IDEA adds in commit:

I'm not sure that is convenient

[whyoleg]

Hm, may be we can commit full vcs.xml file here? Looks like it only contains submodules location with relative paths, so may be it will be fine?
WDYT?

[vmishenev]

I think It should be ok. I have no preferences about it.

[IgnatBeresnev]

Hm, may be we can commit full vcs.xml file here?

I also don't mind as long as there's no specific settings tailored for one person, but if it happens - it might be possible to add vcs.xml to .gitignore, but still commit and push the base version of it. So that it's updated when you pull, but the automatic changes in it are ignored — that would be the ideal solution

[whyoleg]

I've pushed vcs.xml with full content to the branch, so now it could merged to master.
Regarding .gitignore - I've researched a bit, and found out, that after file is committed to git repository - .gitignore doesn't work for this file anymore...
The only way to ignore changes for committed file is to do something like this: https://stackoverflow.com/a/10755704 - but this is local settings