Rename '-ensure-packages' to -install-selected-packages'

* doc/emacs/package.texi (Fetching Package Sources): Rename instances.
* lisp/emacs-lisp/package-vc.el (package-vc-ensure-packages): Rename
to 'package-vc-install-selected-packages'.
(package-vc-selected-packages): Call renamed function.

doc/emacs/package.texi

@@ -559,7 +559,7 @@ package, without adding it to the package list, use
 @code{package-vc-checkout}.
 
 @vindex package-vc-selected-packages
-@findex package-vc-ensure-packages
+@findex package-vc-install-selected-packages
   An alternative way to use @code{package-vc-install} is via the
 @code{package-vc-selected-packages} user option.  This is an alist of
 packages to install, where each key is a package name and the value is
@@ -567,8 +567,8 @@ packages to install, where each key is a package name and the value is
 indicating a specific revision or a package specification plist.  The
 side effect of setting the user option is to install the package, but
 the process can also be manually triggered using the function
-@code{package-vc-ensure-packages}.  Here is an example of how the user
-option:
+@code{package-vc-install-selected-packages}.  Here is an example of
+how the user option:
 
 @example
 @group

lisp/emacs-lisp/package-vc.el

@@ -118,7 +118,7 @@ the `clone' function."
   :version "29.1")
 
 (defvar package-vc-selected-packages) ; pacify byte-compiler
-(defun package-vc-ensure-packages ()
+(defun package-vc-install-selected-packages ()
   "Ensure packages specified in `package-vc-selected-packages' are installed."
   (pcase-dolist (`(,name . ,spec) package-vc-selected-packages)
     (when (stringp name)
@@ -162,7 +162,7 @@ function `package-vc-selected-packages' to apply the changes."
                                          (:vc-backend symbol)))))
   :set (lambda (sym val)
          (custom-set-default sym val)
-         (package-vc-ensure-packages))
+         (package-vc-install-selected-packages))
   :version "29.1")
 
 (defvar package-vc--archive-spec-alist nil