Checkmk Werk 15906: apc_symmetra: Improve wording in ruleset

ID: 15906 Title: apc_symmetra: Improve wording in ruleset Component: Checks & agents Level: 1 Class: Bug fix Version: 2.3.0b1 The rule 'Levels of battery parameters after calibration' was actually referring to the time after diagnostics and not calibration. This has now been corrected and it's clearer what the rule refers to.