Change the 'instance help' message kind to 'info'

Do this because the 'warning' kind is not the valid one for this message.

Author: HugoGGuerrier

lkql_checker/src/gnatcheck-rules-rule_table.adb

@@ -1052,9 +1052,9 @@ package body Gnatcheck.Rules.Rule_Table is
                 then To_String (Instance.Defined_At)
                 else "command line") & Diag_Defined_At);
             if not Instance_Help_Emitted then
-               Warning
+               Info
                  ("if you want to pass multiple parameters to a rule you " &
-                  "should use the comma separated notation: e.g. " &
+                  "should use the comma separated notation: e.g. "         &
                   "+RMy_Rule:Param1,Param2");
                Instance_Help_Emitted := True;
             end if;

testsuite/tests/gnatcheck_errors/same_name_instances/test.out

@@ -2,7 +2,7 @@ In rule options
 ===============
 
 gnatcheck: rule instance with the same name already exists: "same_alias" previously instantiated at command line
-gnatcheck: if you want to pass multiple parameters to a rule you should use the comma separated notation: e.g. +RMy_Rule:Param1,Param2
+if you want to pass multiple parameters to a rule you should use the comma separated notation: e.g. +RMy_Rule:Param1,Param2
 gnatcheck: rule instance with the same name already exists: "comp_check" previously instantiated at command line
 gnatcheck: rule instance with the same name already exists: "comp_check" previously instantiated at command line
 >>>program returned status code 5
@@ -11,12 +11,12 @@ In command-line
 ===============
 
 gnatcheck: rule instance with the same name already exists: "goto_statements" previously instantiated at command line
-gnatcheck: if you want to pass multiple parameters to a rule you should use the comma separated notation: e.g. +RMy_Rule:Param1,Param2
+if you want to pass multiple parameters to a rule you should use the comma separated notation: e.g. +RMy_Rule:Param1,Param2
 >>>program returned status code 5
 
 In command-line and rule options
 ================================
 
 gnatcheck: rule instance with the same name already exists: "goto_statements" previously instantiated at command line (rules.txt:1:1)
-gnatcheck: if you want to pass multiple parameters to a rule you should use the comma separated notation: e.g. +RMy_Rule:Param1,Param2
+if you want to pass multiple parameters to a rule you should use the comma separated notation: e.g. +RMy_Rule:Param1,Param2
 >>>program returned status code 5