docs(README): Link to all pertinent tool websites

Avoid ambiguity, and make it more convenient for readers to learn about
any tools they may be unfamiliar with. Only link to each tool the first
time it is mentioned.

README.md

@@ -32,10 +32,12 @@ Hooks for Use With the [pre-commit](https://pre-commit.com) Framework
 <!--TOC-->
 
 Pre-commit only supports [Git](https://git-scm.com/) and no other version
-control system (VCS). The defaults for the Yarn hooks are configured for use
-with a [Zero-Installs](https://yarnpkg.com/features/zero-installs)
+control system (VCS). The defaults for the [Yarn](https://yarnpkg.com/) hooks
+are configured for use with a
+[Zero-Installs](https://yarnpkg.com/features/zero-installs)
 [TypeScript](https://www.typescriptlang.org/) project. They assume Yarn and
-Node.js are managed by asdf, but the file patterns may be overridden.
+[Node.js](https://nodejs.org/) are managed by [asdf](https://asdf-vm.com/), but
+the file patterns may be overridden.
 
 ## Hooks
 
@@ -54,8 +56,8 @@ Install tools (based on `.tool-versions` unless otherwise configured) by running
 
 Validate structure of `pyproject.toml` by running
 [`poetry check`](https://python-poetry.org/docs/cli/#check). Run when
-Poetry dependencies or version changes (assuming Poetry is managed by asdf, but
-the file pattern may be overridden).
+[Poetry](https://python-poetry.org/) dependencies or version changes (assuming
+Poetry is managed by asdf, but the file pattern may be overridden).
 
 ### `poetry-lock`
 
@@ -79,8 +81,8 @@ See also the documentation for
 
 ### `megalinter`
 
-Run MegaLinter on files modified relative to default branch (skipping jscpd)
-by running:
+Run [MegaLinter](https://megalinter.github.io/) on files modified relative to
+default branch (skipping jscpd) by running:
 
 ```sh
 npx -- mega-linter-runner@<version> \