add node:lts section

Author: MikeMcC399

README.md

@@ -22,6 +22,7 @@ The official Node.js docker image, made with love by the node community.
     - [npm run](#npm-run)
 - [Image Variants](#image-variants)
   - [`node:<version>`](#nodeversion)
+  - [`node:lts`](#nodelts)
   - [`node:alpine`](#nodealpine)
   - [`node:bullseye`](#nodebullseye)
   - [`node:bookworm`](#nodebookworm)
@@ -172,6 +173,11 @@ on their system. It, by design, has a large number of extremely common Debian
 packages. This reduces the number of packages that images that derive from it
 need to install, thus reducing the overall size of all images on your system.
 
+### `node:lts`
+
+This is a special form of `node:<version>` that selects the
+Active Long Term Support version of Node.js. See also [Long Term Support](#long-term-support-lts) below for more detail.
+
 ### `node:alpine`
 
 This image is based on the popular
@@ -239,7 +245,8 @@ Production applications should only use Active LTS or Maintenance LTS releases.
 Refer to [Node.js Releases](https://github.com/nodejs/release#readme) for a description
 of release phases and schedule.
 
-If no version selection is made in a tag, then the Current release is selected.
+If no version selection is made in a tag, for example, `node:slim`,
+then the Current release is selected.
 `node` images using the Active LTS release are published with an `lts` floating tag
 to aid their selection. `node:lts` can be used on its own, or in combination with other tags
 such as `node:lts-slim`. To select a `node` image based on a Maintenance LTS version