update sa6005: tips use !strings.EqualFold when token is NEQ

[alingse]

xyz.go:55:13: SA6005: should use strings.EqualFold instead (staticcheck)
} else if strings.ToUpper(a) != strings.ToUpper(b) {

this message may cause some misstake when copy the method and change it to

} else if strings.EqualFold(a, b) {

a better tips we think should be

xyz.go:55:13: SA6005: should use !strings.EqualFold instead (staticcheck)
} else if strings.ToUpper(a) != strings.ToUpper(b) {

[alingse]

@dominikh how do you think? 🤔