Fix wording in API param comment

ee/lib/api/helpers/vulnerability_findings_helpers.rb

@@ -13,7 +13,7 @@ module API
                  default: 'dismissed', values: %w[all dismissed]
         optional :severity,
                  type: Array[String],
-                 desc: 'Returns issues belonging to specified severity level: '\
+                 desc: 'Returns vulnerabilities belonging to specified severity level: '\
                        '`undefined`, `info`, `unknown`, `low`, `medium`, `high`, or `critical`. Defaults to all',
                  values: ::Vulnerabilities::Occurrence.severities.keys,
                  default: ::Vulnerabilities::Occurrence.severities.keys