SONARKT-400 Migrate GraphemeClustersInClassesCheck to kotlin-analysis-api

Author: leveretka

sonar-kotlin-checks/src/main/java/org/sonarsource/kotlin/checks/GraphemeClustersInClassesCheck.kt

@@ -22,7 +22,6 @@ import org.sonarsource.analyzer.commons.regex.finders.GraphemeInClassFinder
 import org.sonarsource.kotlin.api.regex.AbstractRegexCheck
 import org.sonarsource.kotlin.api.regex.RegexContext
 
-@org.sonarsource.kotlin.api.frontend.K1only
 @Rule(key = "S5868")
 class GraphemeClustersInClassesCheck : AbstractRegexCheck() {
     override fun visitRegex(regex: RegexParseResult, regexContext: RegexContext) {