Resolve "There is nothing about ZSH"

Closes #216 (closed), #217 (closed)

doc.zih.tu-dresden.de/docs/software/zsh.md

 # ZSH
 
+!!! warning
+    Though all efforts have been made to ensure the accuracy and 
+    currency of the content on this website, please be advised that 
+    some content might be out of date and there is no continuous 
+    website support available. In case of any ambiguity or doubts, 
+    users are advised to do their own research on the content's 
+    accuracy and currency.
+
 The ZSH, short for `z-shell`, is an alternative shell for Linux that offers many convenience features
 for productive use that `bash`, the default shell, does not offer.
 
@@ -96,7 +104,7 @@ mcd () {
 You can then
 
 ```
-marie@login$ mcd non-existant-directory
+marie@login$ mcd non-existent-directory
 ```
 
 and it will create it and `cd` into it