Use new keywords for examples in index.md

docs/docs/index.md

@@ -19,9 +19,9 @@ applicazioni verbose, eccetera]
   `grep` is powerful, but sometimes you want something more expressive:
 
 ```
-circolog-tail -where 'app_name=="apache" and message LIKE "%memory%"'
-circolog-tail -where '(app_name"apache" OR app_name LIKE "php%") AND message LIKE "%memory%"'
-circolog-tail -where 'app_name=="mysql" OR severity >= warning'
+circolog-tail -where 'prog=="apache" and msg LIKE "%memory%"'
+circolog-tail -where '(prog=="apache" OR prog LIKE "php%") AND msg LIKE "%memory%"'
+circolog-tail -where 'prog=="mysql" OR sev >= warning'
 ```
 
 - Colors: highlight severity and visually group related message