update docs

docs/30_Usage.md

@@ -86,9 +86,14 @@ slack[]='{ "#support-channel": "https://hooks.slack.com/services/XXXXXX/YYYYYY/Z
 ["hello plugin"]
 description="I sust wann say hello"
 function="hello"
-params='{
-"message": "Here I am"
-}'
+
+; JSON example ... variables cannot be expanded
+; params='{
+;     "message": "Here I am"
+; }'
+;
+; ... but in double quotes the expansion works
+params[message]="Here is ${USER}"
 
 ; -----------------------------------------------------------------------
 ```
@@ -109,16 +114,12 @@ The binary uses the php function `parse_ini_file` - see <https://www.php.net/man
 
   * numbers of integer, float (no quoting)
   * strings in single quotes or double quotes
-  * Specialties: We use JSON syntax in these ini variables to parse
-    * [notifications] -> slack
-    * [check] -> params
-  * Environment variables or PHP configuration values can be embedded using `${<VARMAME>}`; it works with unquoted value or double quoted strings but not inside single quotes.
-
-In the example above see the value behind `params=`. It is aquoted string using single quotes `'`. The JSON key and value must be quoted with double quotes.
+  * Specialty: In [check] -> params you can use JSON syntax: It is aquoted string using single quotes `'`. The JSON key and value must be quoted with double quotes.
+  * Environment variables or PHP configuration values can be embedded using `${<VARMAME>}`; it works with unquoted value or double quoted strings but not inside single quotes (or JSON).
 
 The values for each check are check specific. Have a look to the origin docs for each check - see <https://os-docs.iml.unibe.ch/appmonitor/PHP_client/Plugins/Checks/index.html>.
 
-To have a minimal working example have a the folder `tests/configs` or here <https://git-repo.iml.unibe.ch/iml-open-source/appmonitor-cli-client/-/tree/main/tests/configs?>. But here are not all supported keys.
+To have a minimal working example have a the folder `tests/configs` or here <https://git-repo.iml.unibe.ch/iml-open-source/appmonitor-cli-client/-/tree/main/tests/configs?>. These ini files do NOT contain all supported keys.
 
 ## Exitcodes