add package-vc to standard install prelude

Signed-off-by: Psionik K <73710933+psionic-k@users.noreply.github.com>

Author: psionic-k

doc/manual.org

@@ -111,6 +111,12 @@ working with Elisp packages, Elisp Repo Kit provides shortcuts:
  #+begin_src elisp
    (use-package erk) ; vanilla, assuming you have MELPA configured
 
+   ;; package-vc
+   (package-vc-install
+    '(erk :url "https://github.com/positron-solutions/elisp-repo-kit.git"
+          :lisp-dir "lisp"
+          :doc "doc/erk.texi"))
+
    ;; using elpaca's with explicit recipe
    (use-package erk
      :elpaca (erk :host github :repo "positron-solutions/elisp-repo-kit"))