Keep path when creating a new branch (#21153)

If you are create a new new branch while viewing file or directory, you
get redirected to the root of the repo. With this PR, you keep your
current path instead of getting redirected to the repo root.

services/forms/repo_branch_form.go

@@ -16,6 +16,7 @@ import (
 // NewBranchForm form for creating a new branch
 type NewBranchForm struct {
 	NewBranchName string `binding:"Required;MaxSize(100);GitRefName"`
+	CurrentPath   string
 	CreateTag     bool
 }