Made string lowercase before making it sentence case

string_utils/string_utils.go

@@ -238,8 +238,10 @@ func KeyToHumanReadable(s string) string {
 }
 
 func SentenceCase(str string) string {
-	for i, v := range str {
-		return string(unicode.ToUpper(v)) + str[i+1:]
+	if len(str) > 0 {
+		str = strings.ToLower(str)
+		r := []rune(str)
+		return string(append([]rune{unicode.ToUpper(r[0])}, r[1:]...))
 	}
 	return ""
 }