[gtk] cssdimensionvalue: Remove an outdated comment

[Timm Bäder <baedert src gnome org>]

commit a16e1cbf189ba36777b8a2ed93b3bf3d2d46426b
Author: Timm Bäder <mail baedert org>
Date:   Sat Jan 25 19:59:12 2020 +0100

    cssdimensionvalue: Remove an outdated comment
    
    It's actually implemented in gtkcssdimensionvalue.c these days.

 gtk/gtkcssdimensionvalueprivate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkcssdimensionvalueprivate.h b/gtk/gtkcssdimensionvalueprivate.h
index f13a9281bb..fea2a919ef 100644
--- a/gtk/gtkcssdimensionvalueprivate.h
+++ b/gtk/gtkcssdimensionvalueprivate.h
@@ -26,7 +26,7 @@ G_BEGIN_DECLS
 
 GtkCssValue *   gtk_css_dimension_value_new         (double                  value,
                                                      GtkCssUnit              unit);
-/* This function implemented in gtkcssparser.c */
+
 GtkCssValue *   gtk_css_dimension_value_parse       (GtkCssParser           *parser,
                                                      GtkCssNumberParseFlags  flags);