chore(kb): marginally improve articles

knowledge base/shellcheck.md

@@ -2,26 +2,47 @@
 
 Gives warnings and suggestions about `bash`/`sh` shell scripts.
 
-## Table of contents <!-- omit in toc -->
-
 1. [TL;DR](#tldr)
 1. [Further readings](#further-readings)
 
 ## TL;DR
 
+<details>
+  <summary>Installation and configuration</summary>
+
 ```sh
-shellcheck /path/to/script.sh
+apt install 'shellcheck'
+brew install 'shellcheck'
+pacman -S 'shellcheck'
+zypper in 'ShellCheck'
 ```
 
+</details>
+<details>
+  <summary>Usage</summary>
+
+```sh
+shellcheck '/path/to/script.sh'
+shellcheck '/path/to/scripts/*.sh'
+```
+
+</details>
+
 ## Further readings
 
 - [Website]
 - [Github]
 
 <!--
-  References
+  Reference
+  ═╬═Time══
   -->
 
+<!-- In-article sections -->
+<!-- Knowledge base -->
+<!-- Files -->
 <!-- Upstream -->
 [github]: https://github.com/koalaman/shellcheck
 [website]: https://www.shellcheck.net/
+
+<!-- Others -->