Mention module commands in maxadmin document

The document explains how the module commands are used and gives an
example how they could be used.

Also fixed a few references to the old command names.

Documentation/Reference/MaxAdmin.md

@@ -1425,6 +1425,33 @@ until the next restart.
 Usage: destroy monitor NAME
 ```
 
+## Other Modules
+
+Modules can implement custom commands called _module commands_. These are
+intended to allow modules to perform very specific tasks.
+
+To list all module commands, execute `list commands` in maxadmin. This shows all
+commands that the modules have exposed. It also explains what they do and what
+sort of arguments they take.
+
+If no module commands are registered, no output will be generated. Refer to the
+module specific documentation for more details about module commands.
+
+To call a module commands, execute `call command <domain> <command>` in
+maxadmin. The _<domain>_ is the name of the module and _<command>_ is the
+command that should be called. The commands take a variable amount of arguments
+which are explained in the output of `list commands`.
+
+An example of this is the `dbfwfilter` module that implements a rule reloading
+mechanism as a module command. This command takes a filter name as a parameter.
+
+```
+maxadmin call command dbfwfilter rules/reload my-firewall-filter /home/user/rules.txt
+```
+
+Here the name of the filter is _my-firewall-filter_ and the optional rule file
+path is `/home/user/rules.txt`.
+
 # Tuning MariaDB MaxScale
 
 The way that MariaDB MaxScale does it’s polling is that each of the polling

Documentation/Reference/Module-Commands.md

@@ -5,10 +5,10 @@ commands. They allow the modules to expand beyond the capabilities of the
 module API. Currently, only MaxAdmin implements an interface to the module
 commands.
 
-All registered module commands can be shown with `maxadmin list functions` and
+All registered module commands can be shown with `maxadmin list commands` and
-they can be executed with `maxadmin call function <domain> <name> ARGS...` where
+they can be executed with `maxadmin call command <domain> <name> ARGS...` where
-_<domain>_ is the domain where the module registered the function and _<name>_
+_<domain>_ is the domain where the module registered the command and _<name>_
-is the name of the function. _ARGS_ is a function specific list of arguments.
+is the name of the command. _ARGS_ is a function specific list of arguments.
 
 ## Developer reference
 
@@ -16,6 +16,8 @@ The module command API is defined in the _modulecmd.h_ header. It consists of
 various functions to register and call module commands. Read the function
 documentation in the header for more details.
 
+**Note:** The domain should match the name of the module.
+
 The following example registers the module command _my_command_ in the _my_module_ domain.
 
 ```