Show rebase head in the graph during rebase

[Mingun]

Currently, if you start rebase outside of SourceGit, and stop for edit files, you cannot see the commit chain to the currently edited commit. I think, this feature slightly interleaved with #1673

Steps to reproduce:

1. Open SourceGit
2. Start rebase from CLI and mark some commit as edit
3. See that in SourceGit you doesn't see that commit and all already rebased commits in the graph

[love-linger]

Please check that you have no history filters

[Mingun]

Yes, I have some branches hidden in the revision graph, because this is git-svn repository and those branches are outdated. If remove that filters, the HEAD mark will be visible. But I expect that if you have filters that only excludes some branches / tags, all other refs should be visible!

[Mingun]

In any case, even if you have filters, that includes something, I think, you should show dynamically appearing refs because you cannot setup filters for them ahead of time.

[love-linger]

But I expect that if you have filters that only excludes some branches / tags, all other refs should be visible!

If we always include HEAD when we only have excluded filters, we can never exclude the current branch even if we added it to excluded filters because that HEAD is just another pointer that refs to it.

In any case, even if you have filters, that includes something, I think, you should show dynamically appearing refs because you cannot setup filters for them ahead of time.

SourceGit will auto-add the new created/checkouted branch (not detached, must has a stable refs name) into filters if we only have included filters.

[love-linger]

I've pushed a new commit that when we only have excluded filters and is cherry-picking/rebasing/merging/reverting, add HEAD to show-list

[Mingun]

Thanks!

If we always include HEAD when we only have excluded filters, we can never exclude the current branch even if we added it to excluded filters because that HEAD is just another pointer that refs to it.

It is easy to avoid if before adding HEAD check if it points to the same commit as one of refs in the filter.