chore: add shellcheck

docs/2023-06-25-useful-tools.html

@@ -493,6 +493,11 @@
           >https://github.com/burntsushi/toml</a
         >
       </li>
+      <li>
+        <a href="https://github.com/koalaman/shellcheck"
+          >https://github.com/koalaman/shellcheck</a
+        >
+      </li>
       <li>
         <a href="https://github.com/bojand/ghz"
           >https://github.com/bojand/ghz</a

posts/2023-06-25-useful-tools.md

@@ -121,6 +121,7 @@ Memory
 - https://github.com/gitleaks/gitleaks
 - https://github.com/tailscale/golink
 - https://github.com/burntsushi/toml
+- https://github.com/koalaman/shellcheck
 - https://github.com/bojand/ghz
 - https://github.com/sharkdp/hyperfine
 - https://github.com/boyter/cs