checker: add check for using a private const in another module (#8501)

vlib/gx/text.v

@@ -7,8 +7,8 @@ const (
 )
 
 // TODO: remove these and uae the enum everywhere
-const (
-	align_left = HorizontalAlign.left
+pub const (
+	align_left  = HorizontalAlign.left
 	align_right = HorizontalAlign.right
 )
 
@@ -28,9 +28,9 @@ pub enum VerticalAlign {
 pub struct TextCfg {
 pub:
 	color          Color = black
-	size           int = 16
+	size           int   = 16
 	align          HorizontalAlign = .left
-	vertical_align VerticalAlign = .top
+	vertical_align VerticalAlign   = .top
 	max_width      int
 	family         string
 	bold           bool