all: rename packages ending with "util" to end with "x" (#8182)

Co-authored-by: JSS <jss@unknwon.dev>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

internal/dbutil/string_test.go

@@ -1,21 +0,0 @@
-package dbutil
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-
-	"gogs.io/gogs/internal/conf"
-)
-
-func TestQuote(t *testing.T) {
-	conf.UsePostgreSQL = true
-	got := Quote("SELECT * FROM %s", "user")
-	want := `SELECT * FROM "user"`
-	assert.Equal(t, want, got)
-	conf.UsePostgreSQL = false
-
-	got = Quote("SELECT * FROM %s", "user")
-	want = `SELECT * FROM user`
-	assert.Equal(t, want, got)
-}