* create new action: git switch
If the branch already exists in local, switch to that.
If the branch is only in remote, create new branch tracking remote and switch to new one.
* fix a point of review
* fix a point of review: map to git-switch action
* Revert "fix a point of review"
This reverts commit 017ce424a3adfe1b3712a421385cfc3f4258a0fb.
* undocument header comment