Allow to restore/fetch file(s) from another branch

[kwin]

Description

As explained in https://stackoverflow.com/questions/2364147/how-to-get-just-one-file-from-another-branch both

• git checkout <sourcebranch> -- <filepaths> (https://git-scm.com/docs/git-checkout#Documentation/git-checkout.txt-emgitcheckoutem-f--ours--theirs-m--conflictltstylegtlttree-ishgt--ltpathspecgt82308203) works on the target branch as well as
• git restore --source <sourcebranch> -- <filepaths> (https://git-scm.com/docs/git-restore#Documentation/git-restore.txt---sourcelttreegt)

works on the CLI. Unfortunately there is no equivalent for either of those operations in EGit up till now

Motivation

In order to split up a branch into two separate ones it is often necessary to work based on files in another branch rather than on commits.

Alternatives considered

Using CLI

Additional context

No response

[Bananeweizen]

select branch/commit/ref > show in > history > scroll to wanted file in history view > check out this version

[kwin]

@Bananeweizen Thanks for the pointer, it would be helpful to explicitly add those file checkouts to https://github.com/eclipse-egit/egit/wiki/User-Guide#checking-out-an-existing-branch or a dedicated sibling section.