Resolve "There is nothing about ZSH"

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

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

@@ -150,7 +150,7 @@ function _module {
     MODULE_COMMANDS=(
         '-t:Show computer parsable output'
         'load:Lload a Module'
-        'unload:Unload a Module'
+        'unload:Unload a module'
         'spider:Search for a module'
         'avail:Show available modules'
         'list:List loaded modules'