update apache http doc

docs/20_Checks/check_haproxy_status.md

@@ -3,6 +3,7 @@
 ## Introduction
 
 **check_haproxy_health** show status and connections count on frontend and backend.
+This check sends performance data.
 
 ## Syntax
 

docs/20_Checks/check_http.md

@@ -2,8 +2,14 @@
 
 ## Introduction
 
-Makes an http request with a given method.
-Additionally you can verify the response.
+Makes an http request with a given method (like HEAD or GET; GET is default).
+Additionally you can verify the response:
+
+* check if the status code is the wanted; default: if no code is given it switches to error on status codes > 400
+* check http response header for a given regex; default: no check
+* check http response body for a given regex; default: no check
+* check http response body if a given regex does not exist; default: no check
+* the response body can be filtered with a given filter using ``jq``; default: no filtering
 
 ## Requirements
 
@@ -123,7 +129,7 @@ Found:
 
 ### Exact status code
 
-With ``-m`` you can verify if the status code matches exactly a given value.
+With ``-s`` you can verify if the status code matches exactly a given value.
 You also can set a code for http error to ensure if a protected url really is blocking the request.
 
 Maybe you don't deny the access like