Add vc-create/switch/print-branch to menu and update documentation (bug#63690)

Add vc-create/switch/print-branch to menu and update documentation (bug#63690)

* doc/emacs/maintaining.texi (VC Change Log):
Add 'C-x v b l' (vc-print-branch-log).
(Creating Branches): Add @kindex and @findex for vc-create-branch.
(Switching Branches): Add @kindex and @findex for vc-switch-branch.

* lisp/vc/vc-hooks.el (vc-menu-map): Add menu items for new
commands vc-create-branch and vc-switch-branch, and also
vc-print-branch-log.

* lisp/vc/vc.el (vc-print-branch-log): Improve docstring.