* do NOT modify the existing merge, and add a new constructor for `Commands.Merge` instead
* rewrite `ViewModels.MergeMultiple`
- since `_histories.Commits.Find` may returns null, use `List<object>` instead of `List<Models.Commits>`
- supports display merge target as both `Models.Commit` and `Models.Branch`
* rename translation key `Text.MergeMultiple.Commit` to `Text.MergeMultiple.Targets`, and add translations for zh_CN and zh_TW
* some UI/UX changes
* fix watcher stuck by pull
* make stage area resizeable
---------
Co-authored-by: yindf <yindf@mail.jj.cn>
(cherry picked from commit a842aca042a73cb5fa3995794aae2a2e3540b37f)
* add missing translations and it's no need to add `OnPull` suffix since it already has a prefix `Text.Pull.`
* when enable fetching all branches of selected remote, use merge/rebase command instead of pull
* re-arrange orders of options in pull popup panel
* default enable `Fetch all branches`
* the way to deal with local changes on checkout branch page
* the way to deal with local changes and should checkout after created on new branch page
* should fetch without tags on fetch page
* the way to deal with local changes and should fetch without tags on pull page
* should push all tags on push
* remove dotnet-tool.json because the project does not rely on any dotnet tools.
* remove Directory.Build.props because the solution has only one project.
* move src/SourceGit to src. It's not needed to put all sources into a subfolder of src since there's only one project.
